{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":46600,"title":"Generate a list of composite numbers","description":null,"description_html":"\u003cdiv style = \"text-align: start; line-height: 20.4333px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 114px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407.5px 57px; transform-origin: 407.5px 57px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384.5px 31.5px; text-align: left; transform-origin: 384.5px 31.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 384.475px 7.875px; transform-origin: 384.475px 7.875px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003ePrime numbers get a lot of attention in Cody, while composite numbers get relatively little. Right now a search for \"prime\" on Cody yields 153 problems, while a search for \"composite\" yields only 27--and only eight of those deal with composite numbers. Let's work toward restoring the balance. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384.5px 21px; text-align: left; transform-origin: 384.5px 21px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 382.217px 7.875px; transform-origin: 382.217px 7.875px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function to list the composite numbers less than or equal to the input number. Remember that 1 is neither prime nor composite.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function c = composites(n)\r\n  c = [4 6 etc.];\r\nend","test_suite":"%%\r\nn = 10;\r\nc_correct = [4 6 8 9 10];\r\nassert(isequal(composites(n),c_correct))\r\n\r\n%%\r\nn = 31;\r\nc_correct = [4 6 8 9 10 12 14 15 16 18 20 21 22 24 25 26 27 28 30];\r\nassert(isequal(composites(n),c_correct))\r\n\r\n%%\r\nn = 500;\r\nc = composites(n);\r\nlen_correct = 404;\r\nc_correct80 = [110 207 303 399 495];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(80:80:end),c_correct80))\r\n\r\n%%\r\nn = 50011;\r\nc = composites(n);\r\nlen_correct = 44877;\r\nc_correct8900 = [10146 20070 29942 39782 49594];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(8900:8900:end),c_correct8900))\r\n\r\n%%\r\nn = 3628800;\r\nc = composites(n);\r\nlen_correct = 3370110;\r\nc_correct670000 = [728682 1450680 2170682 2889408 3607220];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(670000:670000:end),c_correct670000))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":46909,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":66,"test_suite_updated_at":"2020-09-22T13:39:30.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2020-09-22T05:11:09.000Z","updated_at":"2026-05-25T05:41:00.000Z","published_at":"2020-09-22T05:33:18.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePrime numbers get a lot of attention in Cody, while composite numbers get relatively little. Right now a search for \\\"prime\\\" on Cody yields 153 problems, while a search for \\\"composite\\\" yields only 27--and only eight of those deal with composite numbers. Let's work toward restoring the balance. \u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWrite a function to list the composite numbers less than or equal to the input number. Remember that 1 is neither prime nor composite.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"}],"problem_search":{"problems":[{"id":46600,"title":"Generate a list of composite numbers","description":null,"description_html":"\u003cdiv style = \"text-align: start; line-height: 20.4333px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: rgb(0, 0, 0); white-space: normal; \"\u003e\u003cdiv style=\"block-size: 114px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407.5px 57px; transform-origin: 407.5px 57px; vertical-align: baseline; \"\u003e\u003cdiv style=\"block-size: 63px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384.5px 31.5px; text-align: left; transform-origin: 384.5px 31.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 384.475px 7.875px; transform-origin: 384.475px 7.875px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003ePrime numbers get a lot of attention in Cody, while composite numbers get relatively little. Right now a search for \"prime\" on Cody yields 153 problems, while a search for \"composite\" yields only 27--and only eight of those deal with composite numbers. Let's work toward restoring the balance. \u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv style=\"block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384.5px 21px; text-align: left; transform-origin: 384.5px 21px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; \"\u003e\u003cspan style=\"block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 382.217px 7.875px; transform-origin: 382.217px 7.875px; unicode-bidi: normal; \"\u003e\u003cspan style=\"\"\u003eWrite a function to list the composite numbers less than or equal to the input number. Remember that 1 is neither prime nor composite.\u003c/span\u003e\u003c/span\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e","function_template":"function c = composites(n)\r\n  c = [4 6 etc.];\r\nend","test_suite":"%%\r\nn = 10;\r\nc_correct = [4 6 8 9 10];\r\nassert(isequal(composites(n),c_correct))\r\n\r\n%%\r\nn = 31;\r\nc_correct = [4 6 8 9 10 12 14 15 16 18 20 21 22 24 25 26 27 28 30];\r\nassert(isequal(composites(n),c_correct))\r\n\r\n%%\r\nn = 500;\r\nc = composites(n);\r\nlen_correct = 404;\r\nc_correct80 = [110 207 303 399 495];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(80:80:end),c_correct80))\r\n\r\n%%\r\nn = 50011;\r\nc = composites(n);\r\nlen_correct = 44877;\r\nc_correct8900 = [10146 20070 29942 39782 49594];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(8900:8900:end),c_correct8900))\r\n\r\n%%\r\nn = 3628800;\r\nc = composites(n);\r\nlen_correct = 3370110;\r\nc_correct670000 = [728682 1450680 2170682 2889408 3607220];\r\nassert(isequal(length(c),len_correct) \u0026\u0026 isequal(c(670000:670000:end),c_correct670000))","published":true,"deleted":false,"likes_count":2,"comments_count":0,"created_by":46909,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":66,"test_suite_updated_at":"2020-09-22T13:39:30.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2020-09-22T05:11:09.000Z","updated_at":"2026-05-25T05:41:00.000Z","published_at":"2020-09-22T05:33:18.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003ePrime numbers get a lot of attention in Cody, while composite numbers get relatively little. Right now a search for \\\"prime\\\" on Cody yields 153 problems, while a search for \\\"composite\\\" yields only 27--and only eight of those deal with composite numbers. Let's work toward restoring the balance. \u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003cw:jc w:val=\\\"left\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWrite a function to list the composite numbers less than or equal to the input number. Remember that 1 is neither prime nor composite.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\",\"relationship\":null}],\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"target\":\"/matlab/document.xml\",\"relationshipId\":\"rId1\"}]}"}],"errors":[],"facets":[[{"value":"Sequences \u0026 Series IV","count":1,"selected":false}],[{"value":"easy","count":1,"selected":false}]],"term":"tag:\"composite numbers\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}