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Recurring Cycle Length (Inspired by Project Euler Problem 26)
Preface: This problem is inspired by Project Euler Problem 26 and uses text from that question to explain what a recurring cycle...

10 months ago

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Determine if input is a perfect number
A perfect number occurs whent the sum of all divisors of a positive integer, except the number itself, equals the number. Examp...

10 months ago

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Largest Twin Primes
<http://en.wikipedia.org/wiki/Twin_prime Twin primes> are primes p1, p2 = p1 + 2 such that both p1 and p2 are prime numbers. Giv...

10 months ago

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Find nearest prime number less than input number
Find nearest prime number less than input number. For example: if the input number is 125, then the nearest prime number whi...

10 months ago

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Sophie Germain prime
In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prim...

10 months ago

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Circular Primes (based on Project Euler, problem 35)
The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime. The...

10 months ago

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Natural numbers in string form
Create a cell array of strings containing the first n natural numbers. Slightly harder than it seems like it should be. Exampl...

10 months ago

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Fix the last element of a cell array
Note: this is lifted directly from <http://www.mathworks.com/matlabcentral/answers/82825-puzzler-for-a-monday Puzzler for a Mond...

10 months ago

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Remove element(s) from cell array
You can easily remove an element (or a column in any dimension) from a normal matrix, but assigning that value (or range) empty....

10 months ago

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Create a cell array out of a struct
Create a cell array out of a (single) struct with the fieldname in the first column and the value in the second column: in: ...

10 months ago

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Sum the Infinite Series
Given that 0 < x and x < 2*pi where x is in radians, write a function [c,s] = infinite_series(x); that returns with the...

10 months ago

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Back to basics - array operations
Without performing actual arithmetic operations on arrays, return feasibility of operation as true or false. True if given opera...

10 months ago

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Mirror Image matrix across anti-diagonal
Given an input number x, create a mirror image matrix 'Y' across the anti-diagonal. For example, if x=3, Y = [1 2 3; ...

10 months ago

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Just another norm problem (JANP)
*Task:* Implement a function that takes a square matrix A and returns a nonzero vector yc which minimizes ...

10 months ago

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Persistent Usage
This Challenge is to implement the Matlab Persistent variable capability. Given a sequence of Calls to a function return the cu...

10 months ago

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String Array Basics, Part 1: Convert Cell Array to String Array; No Missing Values
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

10 months ago

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String Array Basics, Part 3: Convert Cell Array with Missing Values to String Array
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

10 months ago

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middleAsColumn: Return all but first and last element as a column vector
Given input A, return all but the first and last elements, arranged as a column vector. (I.e., all dimensions after the first s...

10 months ago

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String Array Basics, Part 2: Convert String Array to Cell Array; No Missing Values
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

10 months ago

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String Array Basics, Part 4: Convert String Array with Missing Values to Cell Array
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

10 months ago

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Matlab Basics II - Velocity of a particle
A particle is moving in space, such that it's velocity is given by: <<http://s30.postimg.org/5rf1xtvj5/cody1.png>> write a...

10 months ago

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Back to basics 2 - Function Path
Covering some basic topics I haven't seen elsewhere on Cody. Given a string that is the name of a MATLAB function, return a s...

10 months ago

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Create Truth Table of Size according to input
Create a Truth Table Example: n = 3 output = [0 0 0; 0 0 1; 0 1 0; 0 1 1; 1 0 0; 1 0 1; 1 1 0; 1 1 1]

10 months ago

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Golomb's self-describing sequence (based on Euler 341)
The Golomb's self-describing sequence {G(n)} is the only nondecreasing sequence of natural numbers such that n appears exactly G...

10 months ago

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Square Digits Number Chain Terminal Value (Inspired by Project Euler Problem 92)
Given a number _n_, return the terminal value of the number chain formed by summing the square of the digits. According to the P...

10 months ago

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"Look and say" sequence
What's the next number in this sequence? * [0] * [1 0] * [1 1 1 0] * [3 1 1 0] * [1 3 2 1 1 0] This a variant on the w...

10 months ago

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Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

10 months ago

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Integer sequence - 2 : Kolakoski sequence
Get the n-th term of Kolakoski Sequence.

10 months ago

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P(girl likes you | she smiled at you)
Compute the probability Given the input probabilities

10 months ago

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List the Moran numbers
The quotient of a Moran number and its digit sum is prime. For example, 117 and 481 are Moran numbers because 117/(1+1+7) is 13 ...

10 months ago