Problem 43019. Iterative sum of digits of 2^n number

Created by elias GR

Solve Later

{"parts":[{"partUri":"/matlab/document.xml","contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Given n, calculate the number 2^n (where n&gt;=0) and</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:b/></w:rPr><w:t>iterate</w:t></w:r><w:r><w:t> until the sum of the digits is a single-digit number.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Example:</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[ Input  n = 7\n Output sum = 2]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>because 2^7 = 128, and 1+2+8=11 and 1+1=2.</w:t></w:r></w:p></w:body></w:document>","relationship":null}],"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","target":"/matlab/document.xml","relationshipId":"rId1"}]}

<div style = "text-align: start; line-height: 20px; 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: normal; text-decoration: none; white-space: normal; "><div style="display: block; min-width: 0px; padding-top: 0px; vertical-align: baseline; "><div style="font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style="">Given n, calculate the number 2^n (where n&gt;=0) and</span></span><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style=""> </span></span><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style="font-weight: bold; ">iterate</span></span><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style=""> until the sum of the digits is a single-digit number.</span></span></div><div style="font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 2px; text-align: left; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style="">Example:</span></span></div><div style="background-color: rgb(247, 247, 247); border-bottom-left-radius: 4px; border-bottom-right-radius: 4px; border-top-left-radius: 4px; border-top-right-radius: 4px; margin-bottom: 10px; margin-left: 3px; margin-right: 3px; margin-top: 10px; margin-left: 3px; margin-top: 10px; margin-bottom: 10px; margin-right: 3px; "><div style="background-color: rgba(0, 0, 0, 0); border-bottom-left-radius: 0px; border-bottom-right-radius: 0px; border-inline-end: 1px solid rgb(233, 233, 233); border-inline-start: 1px solid rgb(233, 233, 233); border-left-color: rgb(233, 233, 233); border-left-style: solid; border-left-width: 1px; border-right-color: rgb(233, 233, 233); border-right-style: solid; border-right-width: 1px; border-top-left-radius: 0px; border-top-right-radius: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; min-height: 18px; padding-left: 4px; white-space: nowrap; "><span style="border-inline-end: 0px none rgb(0, 0, 0); border-inline-start: 0px none rgb(0, 0, 0); border-left-color: rgb(0, 0, 0); border-left-style: none; border-left-width: 0px; border-right-color: rgb(0, 0, 0); border-right-style: none; border-right-width: 0px; display: inline; margin-right: 45px; min-height: 0px; padding-left: 0px; tab-size: 4; white-space: pre; margin-right: 45px; "><span style="margin-right: 0px; "> Input  </span><span style="border-block-end: 0px none rgb(170, 4, 249); border-block-start: 0px none rgb(170, 4, 249); border-bottom-color: rgb(170, 4, 249); border-inline-end: 0px none rgb(170, 4, 249); border-inline-start: 0px none rgb(170, 4, 249); border-left-color: rgb(170, 4, 249); border-right-color: rgb(170, 4, 249); border-top-color: rgb(170, 4, 249); caret-color: rgb(170, 4, 249); color: rgb(170, 4, 249); column-rule-color: rgb(170, 4, 249); margin-right: 0px; outline-color: rgb(170, 4, 249); text-decoration-color: rgb(170, 4, 249); ">n = 7</span></span></div><div style="background-color: rgba(0, 0, 0, 0); border-bottom-left-radius: 0px; border-bottom-right-radius: 0px; border-inline-end: 1px solid rgb(233, 233, 233); border-inline-start: 1px solid rgb(233, 233, 233); border-left-color: rgb(233, 233, 233); border-left-style: solid; border-left-width: 1px; border-right-color: rgb(233, 233, 233); border-right-style: solid; border-right-width: 1px; border-top-left-radius: 0px; border-top-right-radius: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; min-height: 18px; padding-left: 4px; white-space: nowrap; "><span style="border-inline-end: 0px none rgb(0, 0, 0); border-inline-start: 0px none rgb(0, 0, 0); border-left-color: rgb(0, 0, 0); border-left-style: none; border-left-width: 0px; border-right-color: rgb(0, 0, 0); border-right-style: none; border-right-width: 0px; display: inline; margin-right: 45px; min-height: 0px; padding-left: 0px; tab-size: 4; white-space: pre; margin-right: 45px; "><span style="margin-right: 0px; "> Output </span><span style="border-block-end: 0px none rgb(170, 4, 249); border-block-start: 0px none rgb(170, 4, 249); border-bottom-color: rgb(170, 4, 249); border-inline-end: 0px none rgb(170, 4, 249); border-inline-start: 0px none rgb(170, 4, 249); border-left-color: rgb(170, 4, 249); border-right-color: rgb(170, 4, 249); border-top-color: rgb(170, 4, 249); caret-color: rgb(170, 4, 249); color: rgb(170, 4, 249); column-rule-color: rgb(170, 4, 249); margin-right: 0px; outline-color: rgb(170, 4, 249); text-decoration-color: rgb(170, 4, 249); ">sum = 2</span></span></div></div><div style="font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-bottom: 9px; margin-left: 4px; margin-right: 10px; margin-top: 10px; text-align: left; white-space: pre-wrap; margin-left: 4px; margin-top: 10px; margin-bottom: 9px; margin-right: 10px; "><span style="display: inline; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; "><span style="">because 2^7 = 128, and 1+2+8=11 and 1+1=2.</span></span></div></div></div>

Solve

Solution Stats

75 Solutions
28 Solvers

Last Solution submitted on Oct 16, 2022

Last 200 Solutions

Problem Comments

7 Comments

7 Comments

Show 4 older comments

goc3 on 5 Oct 2016

I clarified the problem statement and fixed one test case to make the problem solvable as originally intended.

James on 6 Oct 2016

Anyone else running into an issue with 2^111? I'm getting 2^111 = 2596148429267413814265248164610048, which sums to 143, which sums to 8. The test suite says 9.

Binbin Qi on 11 Nov 2016

The last test is not correct. Could you check it ?

Jean-Marie Sainthillier on 30 May 2017

Yes, this is a sequence (1 2 4 8 7 5 1 2 4 8 7 5 ...)

ChrisR on 12 Jul 2021

The test with n = 111 is still incorrect.

Ramon Villamangca on 27 Oct 2021

is should be 8 for n = 111. am I missing something?

goc3 on 12 Apr 2022

The last test case has been fixed.

Problem Recent Solvers28

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 43019. Iterative sum of digits of 2^n number

Solution Stats

Last 200 Solutions

Problem Comments

Problem Recent Solvers28

Suggested Problems

More from this Author2

Problem Tags

Community Treasure Hunt

Problem 43019. Iterative sum of digits of 2^n number

Solution Stats

Last 200 Solutions

Problem Comments

Problem Recent Solvers28

Suggested Problems

More from this Author2

Problem Tags

Community Treasure Hunt

Players