# Questions tagged [factorial]

This tag is for challenges involving the factorial of a number, the product of the numbers from 1 to n

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### Factorials of primes decomposition

You have to decompose a positive integer/fraction as a product of powers of factorials of prime numbers. For example ...
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### Find a factorial with n trailing zeros, quickly

Problem A fact you may have noticed about factorials is that as $n$ gets larger $n!$ will have an increasing number of $0$s at the end of it's base $10$ representation. In fact this is true ...
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### Calculate the (n x "super")factorial [duplicate]

Introduction Factorials are one of the most frequently used examples to show how a programming language works. A factorial, denoted $n!$, is $1⋅2⋅3⋅…⋅(n-2)⋅(n-1)⋅n$. There is also the ...
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### Implement the Torian

The Torian, $x!x$, of a non-negative integer $x$ can be recursively defined as $$x!0 = x \\ x!n = \prod^x_{i=1} i!(n-1) = 1!(n-1) \times 2!(n-1) \times \cdots \times x!(n-1)$$ The Torian is then ...
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### Zeroes at end of $n!$ in base $m$

Related: Zeroes at the end of a factorial Today, we are going to calculate how many zeroes are there at the end of $n!$ (the factorial of $n$) in base $m$. Or in other words: For given integers \...
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### The vanilla factorial challenge

Task Given a non-negative integer $n$, evaluate the factorial $n!$. The factorial is defined as follows: $$n!=\begin{cases}1 & n=0\\n\times(n-1)!&n>0\end{cases}$$ Rules All default I/...
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### Prime Modified Z-Factorials

Let me explain one by one the above terms... We will call $\text{Z-Factorial}(n)$ of a positive integer $n$, $n!$ (i.e. $n$ factorial) without any trailing zeros. So, $\text{Z-Factorial}(30)$...
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### Reverse factorial function

Given a number n, find x such that x! = n, where both x and n are positive integers. Assume the input n will always be the factorial of a positive integer, so something like n=23 will not be given as ...
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### Bad factorial joke

Sometimes I make bad jokes... And a bad joke I like to make involves interpreting exclamation marks in sentences as the factorial sign. Task Your task is to write a program that receives a sentence ...
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### Repeated! Factorials!

Not to be confused with Find the factorial! Introduction The factorial of an integer n can be calculated by $$n!=n\times(n-1)\times(n-2)\times(...)\times2\times1$$...
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