# Questions tagged [number]

A competition to solve a particular problem through the usage and manipulation of numbers.

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### What's my lucky factor?

Lucky numbers (A000959) are numbers generated by applying the following sieve: Begin with the list of natural numbers: ...
3k views

### Exciting Mario Kart Grand Prix - Minimize the point difference!

Introduction When playing Mario Kart the other day, an interesting question popped up when a Grand Prix with my 2 roommates, 9 AI drivers and myself seemed to be fairly close and therefore exciting ...
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### Base-ically god

Story The god of base is opening heaven’s gate for mortals to join the base party. You, as one of the believers, want to follow their steps to ascend to heaven. But not everyone can get in. The god ...
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### Do I need a win streak?

You have played $N$ matches in some game where each match can only result in one of the two outcomes: win or loss. Currently, you have $W$ wins. You want to have a win percentage of $P$ or more, ...
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### You are kinda Replacable to Me

You are provided with a non-empty array $A$ of integers, all greater than 0. But what good is an array if the elements do not sum up to the number $N$ (also provided as input)... So to change that,...
1 vote
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### A problem of rarity [closed]

Given a positive input $n > 0$, output the amout of two types based on their rarity. The two types are called $A$ and $B$, we know the followings: $n$ is a limited input and the maximum is ...
2k views

### Code the Levine sequence

Introduction Note that I learned it from a Numberphile Video, where Neil Sloane explains it better. I recommend you to watch his Video. But for a quick Introduction: The Levine Sequence is made from ...
4k views

### Count all possible Tweets

Challenge This challenge is pretty simple: Output the total number of possible Tweets. Given the fact that $1{,}114{,}112$ Unicode characters exist, and Tweets can be up to $280$ characters long, ...
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### Unique half rainbows

If we take a positive integer $n$ and write out its factors. Someone can determine $n$ just from this list alone. In fact it is trivial to do this since the number is its own largest factor. ...
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### Self-Replicating Numbers

Background For the purpose of this challenge, all numbers and their string representations are assumed to be in decimal (base 10). I tried to find proper terminology for this challenge, but I do not ...
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### Largest power of 2 that divides $n$

Related, related Introduction The ruler sequence is the sequence of the largest possible numbers $a_n$ such that $2^{a_n}\mid n$. It is so-called because its pin plot looks similar to a ruler's ...
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### Liars and Guessers

Github You have probably played, and may even have written a program to play, a simple number guessing game. If so, this probably looks familiar: ...
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### Let's rise higher [closed]

Challenge The main objective of the challenge is pretty simple, this is an answer chaining contest, where you have to serially print numbers from 1. That means User 1's answer will print ...
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### First sequence with no square differences

Consider the sequence $(a_n)$ defined in the following way. $a_0=0$ For all $n=1, 2, 3, \dots$, define $a_n$ to be the smallest positive integer such that $a_n-a_i$ is not a square number, ...
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### Remove excessive occurrences

Given an array $A$ of positive integers between $1$ and $9$ inclusive and a positive integer $n$, remove all integers in $A$ which appear more than $n$ times. For example: ...
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### Print 0 to 100 without 1-9 characters

Print integers 0 to 100 (inclusive) without using characters 123456789 in your code. Separator of numbers can be comma or white space (by default <blank>, <... 838 views

### Golf this Thumb-2 Constant!

One thing that is constantly frustrating when golfing ARM Thumb-2 code is generating constants. Since Thumb only has 16-bit and 32-bit instructions, it is impossible to encode every immediate 32-bit ...
5k views

### Ginormous number

Output this 1364-digit base-10 number: ...
769 views

### Close(st) Binary Boxes

Challenge: Given a list of non-negative integers, determine by how much you should increase each item to create the closest binary box with the resulting integer-list. What is a binary box? A binary ...
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### Diophantine Approximation: find lowest possible denominator to approximate within given precision

Challenge Given a number x and a precision e, find the lowest positive integer q such that <...
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### Implement the Polygamma function

The Polygamma function of order $m$, $\psi^{(m)}(z)$, is the $(m + 1)$th derivative of the logarithm of the gamma function, which is also the $m$th derivative of the digamma function. Your ...
760 views

### Number chopping: Split a number into its digits [closed]

Number Splitting Instructions Oh no, my numbers have stuck together! Luckily, we can split them apart with code. Your code should be a function that takes an integer input from stdin or as an argument....
4k views

### Rotate a number

Given a positive number n, rotate its base-10 digits m positions rightward. That is, output the result of ...
824 views

### Descending dungeons of positional systems

The sequence discussed in this challenge is a variant of the Descending Dungeons sequence family. Specifically, the sequence generation rules: ...
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### How many 1's we get

Description Count how many occurrences there are of the digit 1 between two given numbers $[a, b]$, inclusive. For example, from 1 to 100 it should be 21: 1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,...
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### Music with pi and e

Because I forgot to celebrate Pi Day (14.3), let's celebrate with $\pi$, $e$ (Euler's number) and music! Challenge No, we don't have time to eat a pi-pizza, let's make a program. What you need is ...
282 views

### Is it a geometric sequence or not? [closed]

Well, last time I asked for an arithmetic sequence, now comes the geometric sequence Challenge In this challenge, the input will be an unordered set of numbers and the program should be able to tell ...
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### Is it an Arithmetic Sequence or not? [closed]

Challenge In this challenge, the input will be an ordered set of numbers and the program should be able to tell if the set of numbers is an Arithmetic Sequence. Input The input will be a list ...
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### Name the Aztec year

It's time for another Mesoamerican calendar! The Xiuhnelpilli was used by the Aztecs (more properly, the Mexica) to name their years. Each year has a number and a sign. Here's part of the cycle: <...
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### Checking a Windows 95 OEM Key for validity [closed]

Introduction Windows 95 used a very simple algorithm for verifying license keys. The scheme of an OEM license key always looked like this: xxxyy-OEM-NNNNNNN-zzzzz ...
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### The Double-Castle Numbers™

Introduction A double-castle number™ is a positive integer number that has a pattern of \underbrace{a\cdots a}_{m\text{ }a\text{s}}b\underbrace{a\cdots a}_{m\text{ }a\text{s}}b\underbrace{a\...
Background My user ID is 78410, or $1 0 0 1 1 0 0 1 0 0 1 0 0 1 0 1 0_2$. One interesting property of this number is that, in binary, it doesn't have three consecutive identical digits, and yet it ...