78 questions linked to/from Is this number a prime?
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### I want 8 bits for every character!

This is the reverse of this challenge. Given an encoded list of codepoints and the characters used to encode it, you need to decompress it to its original string. For example, given the encoded list <...
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### The Most Wanted Prime Numbers

Output a sequence of all the primes that are of the following form: 123...91011...(n-1)n(n-1)..11109...321. That is, ascending decimal numbers up to some ...
• 7,898
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### It almost works (Robbers' Thread)

Cops' Thread Your challenge is to find an uncracked, unsafe cop on the cops thread, and find an input value for which their code does not do as specified by the challenge. You must use values within ...
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### It almost works (Cops' Thread)

Robbers' Thread Your challenge is to find an existing challenge, and implement it in a way such that certain inputs fail. At least one input must not produce the correct output (use the other ...
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### Recognize most smaller primes with a regex

This time, you are working on a regex. Your regex is meant to approximately full-match the base-10 representations of primes $0 \le p < 1000$, while ignoring any non-numeric string or composite ...
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### Prime decimal representations of prime binary numbers [duplicate]

Problem Statement: Consider a number n in base-10. Find the smallest base-10 integer i greater than ...
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### Orientation Oriented Programming

Write a program for a specific language that in different orientations performs different tasks. Your code should have at least two non-empty lines and at least two non-empty columns and should ...
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### Ah, why is there a bug in my program?

This challenge is inspired by @LuisMendo's MATL answer to my "binary multiples" challenge. Task Pick a code-golf challenge that is open and that has been posted before this one; let me call it the "...
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### Convert a decimal integer to binary only using arithmetic operators

There are 10 types of people in the world, those who understand binary and those who do not. Where are you? Let's see! Challenge Your task is to convert a decimal integer to binary, only using a ...
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### Tips for Creating/Maintaining a Golfing Language

Creating a golfing language can be hard. Let's help budding golfing language creators out and provide some helpful tips on how to create one. I'm looking for tips on: The design process ...
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### Prime parity peregrination

The purpose of this challenge is to graphically depict a walk on the plane, where the direction of each step $k$ is determined by the primality of $k$ and the parity of its binary expansion. ...
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### ​Cuban​ ​Primes

Given a natural number $n$, return the $n$-th cuban prime. Cuban Primes A cuban prime is a prime number of the form $$p = \frac{x^3-y^3}{x-y}$$ where $y>0$ and $x = 1+y$ or $x = 2+y$ ...
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### The number of ways a number is a sum of consecutive primes

Given an integer greater than 1, output the number of ways it can be expressed as the sum of one or more consecutive primes. Order of summands doesn't matter. A sum can consist of a single number (...
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### Compute the minimum $a(n)>a(n-1)$ such that $a(1)+a(2)+\dots+a(n)$ is prime (OEIS A051935)

Background Consider the following sequence (A051935 in OEIS): Start with the term $2$. Find the lowest integer $n$ greater than $2$ such that $2+n$ is prime. Find the lowest integer $n'$ ...
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