Tim

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Sort Except Zeros
Sort the numbers in a vector. But the position of zeros should not be changed. Example: sort_except_zeros( [5 3 0 0 2 4] ) == [...

21 hours ago

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Which Prime
Given two prime numbers, specify the relation between them i.e. - 'Twin Prime', 'Cousin Prime', 'Sexy Prime' or 'None'

15 days ago

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Bessel Polynomials
Return the n-th Bessel polynomial Assume that n is a non-negative finite integer. bessel_poly(0) ans = 1 bessel_poly(1) ...

15 days ago

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List Honaker primes
The number 131 is the 32nd prime number. It is a Honaker prime because the sum of its digits (1+3+1) equals the sum of the digit...

15 days ago

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Find numbers in the Popular Computing Z-sequence
Here’s a quick one. In 1977 the magazine Popular Computing sought “problem situations for which the computer is the best (if not...

19 days ago

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Gallery function, learning
write a Function, edit something or Add something that give us like the following for random n: n=2 ans= [ 0 1 ...

22 days ago

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Radioisotope Thermoelectric Generator (RTG)
Given an isotope's atomic mass (in amu), half-life (in years(a) or days(d)), and average kinetic energy absorbed (of emitted dec...

26 days ago

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Convert Two Character String into a Binary Vector
Given a string "XOXXO" convert it into a binary vector. [1 0 1 1 0] Paul Berglund implemented an optimal method in <http://ww...

28 days ago

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List the nth prime quartet prefix
Prime numbers larger than 5 can end only in 1, 3, 7, or 9, but of course not all numbers ending in these four digits are prime. ...

28 days ago

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Convert Thermocouple output voltage (in mV) to Temperature (in C)
Convert Thermocouples of types (B,E,J,K,N,R,S,T) output junction voltage (in mV) to temperature (in C) using NIST coefficients r...

1 month ago

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Compute the fractional derivative
Cody Problem 1370 asks us to compute the derivative of a polynomial. This problem extends that idea to fractional derivatives, w...

1 month ago

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Pick the die most likely to win
After discussing Rock, Paper, Scissors, Lizard, Spock in The Simpsons and their Mathematical Secrets, Simon Singh writes that in...

1 month ago

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Compute the sum of reciprocals of quadratics
Write a function to compute the following sum: See also Cody Problem 46000.

1 month ago

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Compute a sum involving the totient over divisors of a number
Write a function to compute the following sum: where is the totient function. The sum is computed over the divisors of (inc...

1 month ago

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Nuclear Binding Energy
Compute the approximate nuclear binding energy in MeV using the least-squares fit of the semi-emirical mass formula. Round to th...

1 month ago

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Compute the effective conductivity of a heterogeneous aquifer
Slow flow through soil or another porous medium follows Darcy’s law, which relates the flow of water to the gradient in piezome...

1 month ago

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Sum the elements in rows of the Levine triangle
The Levine triangle starts as follows: Row 0: 2 Row 1: 1 1 Row 2: 1 2 Row 3: 1 1 2 To construct each row, r...

2 months ago

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Identify Ruth-Aaron numbers
After Hank Aaron hit his 715th home run and passed Babe Ruth’s total of 714, Carl Pomerance noticed that the union of the prime ...

2 months ago

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Compute a sum of Ramanujan
Srinivasa Ramanujan defined the following function: Write a function to compute for various values of . See also Cody Proble...

2 months ago

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Find the smallest integer m such that n divides m!
Write a function that takes an integer and finds the smallest integer whose factorial is divisible by . For example, if , then...

2 months ago

Solved

Determine when snow started
R.P. Agnew posed the following problem: It starts snowing in the morning and continues steadily throughout the day. A snowplow t...

2 months ago

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Count unique orderings of vertices of a polygon
Cody Problem 2671 asks us to determine whether four points can be the corners of a rectangle. The points are not necessarily inp...

2 months ago

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Solve an ODE: equation C
Write a function to solve the following ordinary differential equation: with and . The parameter is a constant. The functi...

2 months ago

Solved

Hexagonal Tiling Dots in a Circle
Return how many <http://en.wikipedia.org/wiki/Hexagonal_grid Hexagonal Tiling> grid points there are inside a circle of radius _...

2 months ago

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Shifted Hexagonal Tiling Dots in a Circle
Return how many <http://en.wikipedia.org/wiki/Hexagonal_grid Hexagonal Tiling> grid points there are inside a circle of radius _...

2 months ago

Solved

Label primes with the Erdos-Selfridge classification

2 months ago

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Solve an ODE: equation B

2 months ago

Solved

List Proth primes

3 months ago

Solved

Solve an ODE: equation A