# Questions tagged [primes]

For challenges about identifying and manipulating prime numbers

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Do you know the book Murderous Maths, in the Horrible Science series? In the book, the Laplace Princess' "ridiculous" cipher might be interesting enough and simple enough to be a code-golf challenge. ...
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### Some Prime Peerage

(Randomly inspired by https://mathoverflow.net/q/339890) (Related: 1, 2) Given an input list of distinct prime numbers (e.g., [2, 5, 7]), and a integer ...
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### Is it a Pascal Prime?

It is well known that odd primes will appear in Pascal's triangle exactly twice. However, not all numbers that appear exactly twice in Pascal's triangle are prime. We'll call these numbers Pascal ...
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### Form a list using prime numbers

You have been given N piles of coins. You have decided to divide each of those B1, B2, ..., BN piles among separate groups of people. The amount of people receiving coins has to be a prime number and ...
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### Primes ’n’ Digits

This has no practical purpose but it could be fun to golf. Challenge Given a number n, Count the amount of each digit in n and add 1 to each count Take the prime factorization of n Count the amount ...
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### Is my number Unique

In this challenge we learned a way to encode every positive integer using factor trees. Here is how it works: The empty string has value of 1. (S) where ...
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### Decomposing into primes

Given an integer n, return the number of ways that n can be written as a list of prime numbers. For example, 2323 can be written ...
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### Keep Decoding This Number!

This challenge posed an algorithm for encoding an integer n as another integer r. What follows is a succinct explanation of that ...
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### First and last prime numbers with prime digits of range

Challenge For a given positive integers range, find the first and last prime number entirely composed of prime number digits, exceptionally including 0 (for the digits, a range of 0-2 should output 2-...