Phuong

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Identify Wagstaff primes
The numbers 3, 43, and 2731 are examples of <https://mathworld.wolfram.com/WagstaffPrime.html Wagstaff primes>. Write a func...

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How many Fibonacci numbers?
Find the number of unique Fibonacci numbers (don't count repeats) in a vector of positive integers. Example: x = [1 2 3 4...

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Determine whether a number is a cluster prime
A <https://mathworld.wolfram.com/ClusterPrime.html cluster prime> is an odd prime number _p_ such that all even numbers less tha...

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List the emirps
An emirp is a prime number that becomes a different prime when reversed. The numbers 13, 17, and 149 are emirps, but 11, 19, and...

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Numbers spiral diagonals (Part 2)
Inspired by Project Euler n°28 and 58. A n x n spiral matrix is obtained by starting with the number 1 and moving to the right ...

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Numbers spiral diagonals (Part 1)
Inspired by Project Euler n°28 et 58. A n x n spiral matrix is obtained by starting with the number 1 and moving to the right...

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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...

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Project Euler: Problem 16, Sums of Digits of Powers of Two
2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26. What is the sum of the digits of the number 2^N? Thanks ...

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Longest Collatz Sequence
Inspired by Projet Euler n°14. The Collatz iterative sequence (See Cody problem n° 2103 and 211) is defined for the set of po...

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Large Sum (inspired by Project Euler 13)
Your function will be provided an arbitrary number of numbers of arbitrary sizes as a cell array of strings. Some numbers will b...

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Divisors for big integer
Inspired by Problem 1025 and Project Euler 12. Given n, return the number y of integers that divide N. For example, with ...

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Highly divisible triangular number (inspired by Project Euler 12)
Triangular numbers can be calculated by the sum from 1 to n. For example, the first 10 triangular numbers are: 1, 3, 6, 10, ...

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Project Euler: Problem 11, Largest product in a grid
What is the greatest product of k adjacent numbers in the same direction (up, down, left, right, or diagonally) in a n×n grid ? ...

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Sum of big primes without primes
Inspired by Project Euler n°10 (I am quite obviously a fan). With problem n°250 by Doug, you can find some global methods to co...

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Sums of cubes and squares of sums
Given the positive integers 1:n, can you: 1. Compute twice the sum of the cubes of those numbers. 2. Subtract the square...

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Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

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Project Euler: Problem 9, Pythagorean numbers
A Pythagorean triplet is a set of three natural numbers, a b c, for which, a^2 + b^2 = c^2 For example, 3^2 + 4^2 = 9 + 16 ...

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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 ...

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Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

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Project Euler: Problem 4, Palindromic numbers
A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

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Project Euler: Problem 1, Multiples of 3 and 5
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

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Find the next prime number
Find the next prime number or numbers for given n. For example: n = 1; out = 2; or n = [5 7]; out = [7 11]; ...

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Make a vector of prime numbers
Input(n) - length of vector with prime numbers Output(v) - vector of prime numbers Example: * n=1; v=2 * n=3; v=[2 3 5...

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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...

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Mersenne Primes
A Mersenne prime is a prime number of the form M = 2^p - 1, where p is another prime number. For example, 31 is a Mersenne prim...

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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...

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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...

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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...

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Mersenne Primes vs. All Primes
A Mersenne prime (M) is a prime number of the form M = 2^p - 1, where p is another prime number. <https://www.mathworks.com/matl...

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The Goldbach Conjecture
The Goldbach conjecture asserts that every even integer greater than 2 can be expressed as the sum of two primes. Given the eve...

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