Questions tagged [base-conversion]

Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.

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1answer
260 views

Converting rational numbers to an “alien” data format

For a story I'm writing, I needed to convert 101⅐ (101 + 1/7 if that doesn’t show up for you) into base 47. Expressing an integer in some base brings back memories of first learning how to program ...
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6answers
426 views

Numbers that are palindromes in N bases

Given an non-negative integer n >= 0, output forever the sequence of integers x_i >= 3 that are palindromes in exactly <...
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4answers
183 views

Mr Seckington weights his ternᵃʳʸ [duplicate]

Mr Seckington is a mobile grocer. He drives his van door-to-door selling his produce all around the nearby villages. Mr Seckington needs a method to weigh the produce he is selling so he knows how ...
38
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32answers
4k views

Output numbers up to 2^n-1, “sorted”

Take a positive integer n as input, and output (some of the) decimal numbers that can be created using n bits, ordered in the following way: First list all the numbers that can be created with only ...
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17answers
2k views

Implement a Stopwatch

Implement a simple digital Stopwatch, which will display the time elapsed in seconds and minutes, as described below. Important Please read both Display and Controls sections ! Display Time ...
18
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8answers
638 views

The beautiful pattern drawer (Little cubes included)

The beautiful pattern drawer Good morning PPCG ! The other day, when I was trying to help someone on Stack Overflow, a part of his problem gave me an idea for this challenge. First of all, check ...
9
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1answer
292 views

Negative XOR primes

About a year ago you were asked to find the XOR primes. These are numbers whose only factors are 1 and themselves when performing XOR multiplication in base 2. Now were are going to spice things up ...
13
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4answers
276 views

Convert between balanced bases!

Balanced bases: Balanced bases are essentially the same as normal bases, except that digits can be positive or negative, while in normal bases digits can only be positive. From here on, balanced ...
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12answers
1k views

Output N in base -10

Challenge: In the programming language of your choice, accept an integer as input in base 10, and output it in the negadecimal notation, which is also known as base -10 Example algorithm: This is ...
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47answers
5k views

What is the reverse (binary) bit number?

So you are given a POSITIVE base 10 (decimal) number. Your job is to reverse the binary digits and return that base 10 number. Examples: ...
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21answers
3k views

Converting “0xUsernames”

0xUsernames There's so many people using a messaging service that they're running out of space to store all the usernames! To fix this, they are going to start storing usernames as hexadecimal, where ...
19
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6answers
697 views

Count the characters - bit by bit!

The simple part: Given an input string containing only printable ASCII-characters (space - tilde), count the number of occurrences of each character and return the result on any convenient format. The ...
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9answers
725 views

Sloping Binary Numbers

Given an integer n, output the first n sloping binary numbers, either 0- or 1-indexed. They are called this because of how they ...
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28answers
1k views

The Baum-Sweet Sequence

The Baum-Sweet Sequence (A086747 with a Twist) Take in a positive integer n and print the integers from 1 to n for which the Baum-Sweet sequence returns true. The ...
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2answers
292 views

The Professor's base building number converter

The nutty maths professor wants to encode all of their research using a system sure to fox even the wiliest of their competitors! To this end the professor has decided to change the base of not just ...
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4answers
201 views

The Primitive and Basic Numbers

Your task is to generate the "Primitive and Basic" numbers, which are made like so: Start with 110. Take the digits of its base-1 representation (110 = 11) and interpret them as base-2 digits. This ...
11
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7answers
441 views

Sum digits till Square

Given is any integer x > 0 and any base y > 3. Sum all digits of x (if written in the set base). Multiply this by the highest possible digit (is always base -1). ...
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55answers
6k views

Binary to decimal converter

Binary to decimal converter As far as I can see, we don't have a simple binary to decimal conversion challenge. Write a program or function that takes a positive binary integer and outputs its ...
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9answers
817 views

All the Xenodromes

Introduction A xenodrome in base n is an integer where all of its digits in base n are different. Here are some OEIS sequences of xenodromes. For example, in base 16, ...
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11answers
1k views

Find the Emirps!

An emirp is a non-palindromic prime which, when reversed, is also prime. The list of base 10 emirps can be found on OEIS. The first six are: ...
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23answers
9k views

Count down from “Infinity”

Seems like an impossible task right? Well, it's actually not that hard. If we write the word Infinity as 8-bit binary ASCII code, we'll get: ...
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18answers
1k views

Digital Diversity

A positive integer may be represented in an integer base 1 <= b < inf. When converted to that base it has some number of distinct digits. Any positive ...
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13answers
5k views

Cheating a multiple choice test, part 2

This is sequel to this challenge by Adnan. If you like this challenge, chances are you'll like the other one too. Check it out! A multiple choice test with 8 questions each with 4 choices might have ...
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23answers
1k views

The Base in the mix

Input: A list/array of integers for which each item is in the range of 2-36. Output: The sum of the integers (as base 10), where each next integer is in the base ...
16
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14answers
732 views

Non-palindromic numbers

A strictly non-palindromic number N is a number that isn't a palindrome in any base (in bases 2 to N-2). These numbers are listed on OEIS For example, the number ...
31
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34answers
5k views

What base is this number in?

Here's a nice easy challenge: Given a string that represents a number in an unknown base, determine the lowest possible base that number might be in. The string will only contain ...
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0answers
196 views

Convert to and from signed octal [closed]

Write some code to do the following: Take as its input a signed integer in either signed decimal or signed octal (explained below) If the number is decimal convert it to octal. If it's octal, convert ...
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20answers
840 views

Decompose a number!

Your task is to decompose a number using the format below. This is similar to base conversion, except that instead of listing the digits in the base, you list the <...
14
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6answers
786 views

ASCII Art Mayan Numerals

This challenge is simple. Given a number, output a ascii-art representation of the number, using the Mayan Base-20 numeral system. What is the Mayan system? The Mayans used base 20 to store numbers,...
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1answer
110 views

Negative base conversion [duplicate]

We already have a base conversion question, but not one with negative bases (nope, this doesn't count). (Corresponding wiki article.) You will receive a number (may be negative) and a base (must be ...
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10answers
1k views

Is it really a comcoin?

Very interesting background Comcoins are a currency like any other. The residents of Multibaseania (an economically robust system of city-states with very few residents in a galaxy far, far away) use ...
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7answers
2k views

Primes in Different Bases

Challenge: You are given a base 10 number. For each base from 10 counting down to base 2: Take the original input number as a base 10 string, and remove any digits of the number which are invalid ...
4
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7answers
584 views

Write a program that converts unary input to binary, decimal, and hexadecimal equivalents

Write a program that accepts input (through stdin) as a string of unary numbers delimited by spaces, and prints the equivalent string of numbers in binary, decimal, and hexadecimal. These unary ...
1
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0answers
74 views

Convert a base-10 number into a number of any other base [duplicate]

You have to take a base-10 number (e.g. 735) and another number for the base to convert to, and convert the base-10 number into the equivalent number in the other base. Rules: You aren't allowed to ...
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6answers
3k views

X+Y=Z - but in which base?

The Challenge Given 3 numbers X, Y and Z in base B, ...
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18answers
1k views

Repdigit Base Finding

A repdigit is a natural number that can be written solely by repeating the same digit. For example, 777 is a repdigit, since it's solely composed of the digit ...
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29answers
2k views

Decompose binary into alternating subsequences

This was inspired by Problem 13 - Non-Repeating Binary of HP CodeWars' recent competition. Let's take a random decimal number, say 727429805944311 and look at ...
16
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11answers
885 views

Sum of Binary Substrings

This challenge is simple, given a decimal number, convert to binary, and calculate the sum of the sub-strings of the binary number, whose length is shorter than the original number. Here is an example:...
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11answers
1k views

Octal, Decimal, or Hexadecimal?

Given an input string containing only letters and numbers, write a program or function that prints the possible printable ASCII characters (Hex 20-7E) that correspond with the string's value in bases ...
8
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3answers
295 views

Convert a “mixed-base” string to ASCII

Given an input of a string with bytes that may be in either binary, octal, or hex, output the string's ASCII equivalent. Input will be provided in the following format, for example: ...
26
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3answers
2k views

Residue Number System

In the vein of large number challenges I thought this one might be interesting. In this challenge, we will be using the Residue Number System (RNS) to perform addition, subtraction, and ...
2
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1answer
223 views

“Fouriest” Transform of An Integer [duplicate]

Challenge Inspired by this SMBC comic, discussed on reddit, math.stackexchange, and calculus7, the challenge is to return the lowest base such that a number is "fouriest." Description [From the ...
15
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3answers
765 views

Fibonacci’s sexagesimals

Leonardo da Pisano a.k.a Fibonacci was instrumental in bringing the Hindu-Arabic numeral system into Europe. Before that, mathematicians there worked in base sixty with Roman numerals. For example, ...
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2answers
280 views

Find the nth base-b digit of (b^k-1)^-2

Task Your task is simple. Write a program or function which takes three positive integer arguments n, k, and b in any order, such that 2 ≤ b ≤ 36, and returns or outputs the nth (1-indexed) base-b ...
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29answers
1k views

Zeroes in interval

Your task is to write a function or program that takes two non-negative integers i and k (i ≤...
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14answers
1k views

All your base palindromic belong to us

Generate the sequence number of bases in which n is a palindrome (OEIS A126071). Specifically, the sequence is defined as follows: given a number ...
5
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1answer
240 views

Look and Say sequence in any base

We all already crossed the look and say sequence, and where asked to guess the next element. As its name tells it very well, you just have to say what you see : ...
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9answers
988 views

Base Conversion With Strings

Introduction We've have a few base conversion challenges here in the past, but not many designed to tackle arbitrary length numbers (that is to say, numbers that are long enough that they overflow ...
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6answers
3k views

1+1 = 10, 1+2 = 3

Write a function or program than can do simple arithmetic (addition, subtraction, multiplication and division) in both base 10 and base 2. The function will take a mathematical expression as input, ...
23
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32answers
2k views

Convert a number to Hexadecimal

Challenge Here's a simple one. Write a function or program when given a number in base 10 as input, it will return or print that number's value in Hexadecimal. Examples ...