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Extra colors
Context In the RGB color system used by Matlab, the color is a 1 x 3 / row vector [R G B] with each value/component R, G, B in ...

6 months ago

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Check the integers additive decomposition conjecture
Problem statement A conjecture (I rediscovered ?) related to Goldbach's one states that every integer above 2 can be written ...

6 months ago

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Check p² = 24k + 1, p > 3, the 'golden prime squares' equation
Historical context In december 2023, I / Nicolas Douillet was working on prime squares properties and I found* the formula : ...

6 months ago

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Euclid primes
Historical context Euclid, the greek mathematician proved at his time that the prime numbers set is an infinite. By the way he ...

6 months ago

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Fermat primes
Historical context The french mathematician Pierre de Fermat found the formula to find some prime numbers. He thought / co...

6 months ago

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Ulam primes first formula
Historical context The polish-american mathematician Stanislaw Ulam found the formula to give the first 760 prime numbers ...

6 months ago

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Ulam primes second formula
Historical context The polish-american mathematician Stanislaw Ulam found the formula to give some prime numbers not given...

6 months ago

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Euler primes
Historical context The great swiss mathematician Leonhard Euler found the formula to give some prime numbers. Problem...

6 months ago

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Prime numbers which are the difference of two consecutive cubes
Problem statement Given a positive integer n greater than 2, find the prime numbers less or equal to n and which are the diff...

6 months ago

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Find the first occurence of a given gap between two consecutive prime numbers
Problem statement Given a gap = p' - p between the two consecutive prime numbers p and p', find its first occurence, f. E...

6 months ago

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Molecule Atomic Wt (CHONS) Molecules
Given a molecular equation string determine its atomic weight. Limited atoms of C H O N and S where wts are rounded to [12 1 16...

9 months ago

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Usage of java.math : N Choose K with unlimited precision
Calculate the binomial coefficient nchoosek with full accuracy. This challenge may use the wonderful word of java.math that allo...

9 months ago

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Factorial: Unlimited Size : java.math
This challenge is an application of java.math that allows unlimited precision calculations. The primary reference sites are <ht...

9 months ago

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Frequencies of prime gaps
Given two positive integers n and , write a function which computes the frequency of the gap between two consecutive of the pr...

9 months ago

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Repeat middle rows and columns of an array
Given an MxN numeric array (A), return an array (B) in which the middle rows and columns have each been repeated once. It may be...

9 months ago

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Breaking up a chocolate bar
You've got a chocolate bar of size , and you want to break it up into bite-sized () pieces. How many steps are required to do th...

9 months ago

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Usage of java.math : Add, Multiply, Pow
This challenge is an introduction to the wonderful word of java.math that allows unlimited precision calculations. The primary ...

9 months ago

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Dilate a 3d object sampled on a regular grid
3d objects can be described by a set of points on a regular grid in Euclidean space. Given the n x 3 matrix m defining some numb...

9 months ago

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Primes Faster for Large N
This Challenge is to improve the "primes" function for speed. This may be accomplished by fixing memory usage. The Matlab fun...

9 months ago

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Find number patterns in rows of a matrix...
So I think this may be a hard one, may be it was only hard for me! So here is what it is, I will give a matrix, with some numbe...

9 months ago

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Diagonal & Anti-Diagonal Matrix: Easy
Create a matrix as shown below from "magic" square. For example: if input x=9;then use mgic(x) and create the matrix...

9 months ago

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Backslang, odds are you used it at some point in time...
So backslang is a language that can be used to communicate in an easy decode code, if people know the rules of decoding it. Wel...

9 months ago

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Classify triangles as acute, obtuse, or right
In an acute triangle, the three interior angles are acute, or smaller than 90 degrees. In an obtuse triangle, one angle is obtus...

9 months ago

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Easy Sequences 12: 50th Prime
Write a function that outputs the th prime after a given number . For example, the th prime after is . NOTE: If itself is pr...

9 months ago

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Easy Sequences 11: Factorial Digits without Trailing Zeros
Here is an easy one... It is not difficult to count the number of digits of the factorial of a given number. For example for 'n...

9 months ago

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Easy Sequences 10: Sum of Cumsums of Fibonacci Sequence
The function F(n) is defined as the set of Fibonacci numbers from the first up to the n-th. S(n) is the result of applying to F,...

9 months ago

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Easy Sequences 9: Faithful Pairs
A "faithful number" is a non-prime number that is one less or one more than some prime number but not both. For example, for num...

9 months ago

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Times 2 - START HERE
Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

9 months ago

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Make a rainbow matrix (follow-up to checkerboard matrix)
Given an integer n, make an n-by-n matrix as shown below. The a(1,1) should be 0. As we move away from the top-left, the number ...

9 months ago

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Vandermonde Matrix
Create the Vandermonde Matrix of the given vector. The matrix consists of columns as powers of the vector, so the first column i...

9 months ago