# Questions tagged [math]

The challenge involves mathematics in some central way. Also consider using more specific tags, listed in the tag wiki info.

1,651 questions
Filter by
Sorted by
Tagged with
1k views

• 1,121
164 views

• 12k
2k views

### Delannoy numbers

Consider a grid from $(0,0)$ in the bottom-left corner to $(m,n)$ in the top-right corner. You begin at $(0,0)$, and can only move in one of these three ways: Directly north $(+0, +1)$, ...
924 views

• 12k
1k views

### 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,...
• 4,920
594 views

### The half-step of Fibonacci

Challenge Implement the 1-indexed sequence A054049, which starts like this: ...
• 64.7k
2k views

### How many bystanders will help?

Flavortext The Bystander Effect is a phenomenon where individuals are less likely to help a victim if other people are present. The idea is that as there are more people around, the individual burden ...
• 40.3k
2k views

### How hyperperfect am I?

A $k$-hyperperfect number is a natural number $n \ge 1$ such that $$n = 1 + k(\sigma(n) − n − 1)$$ where $\sigma(n)$ is the sum of the divisors of $n$. Note that $\sigma(n) - n$ is the ...
1k views

### Calculate Home Primes

The Home Prime of an integer $n$ is the value obtained by repeatedly factoring and concatenating $n$'s prime factors (in ascending order, including repeats) until reaching a fixed point (a prime). ...
1k views

### The meeker number sequence

The Meeker numbers are a 7 digit number in form of $abcdefg$, where $a×b=10c+d$ and $d×e=10f+g$. As an example $6742612$ is a meeker number, here $6×7=10×4+2$ and $2×6=10×1+2$, so it is a ...
• 12k
520 views

### Determine Circles

Giving n(any amount) of points (x,y). What's the minimum amount of circles required to cross every point given? Task Your ...
• 1,367
1 vote
213 views

### 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 ...
• 119
1k views

### Multiplicative Persistence #2

We had a challenge on Multiplicative Persistence here. As a recap, to get a multiplicative persistence of a number, do these steps: Multiply all the digits of a number (in base $10$) Repeat Step 1 ...
• 4,621
2k views

### Implement Ash's float division

Ash has a bit of an interesting float division algorithm. It's designed to never return NaN, and things like signed zero and infinity need to be handled. How it ...
• 17.6k
520 views

• 64.7k
2k views

### Quoted rational numbers

Quote notation is a way of expressing rational numbers based on the concept of $p$-adic numbers, written in the form $x'y$. The quote indicates that the number to it's left ($x$) 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 ...
• 4,621