1
vote
3answers
298 views

Project Euler's Problem Number 88

I am tackling Project Euler's problem number 88, which in a nutshell reads: Let $S_n$ be the set of sequences of natural numbers $(s_1,s_2,...,s_n)$ where $s_1\leqslant s_2\leqslant\cdots\leqslant ...
0
votes
2answers
489 views

Want to classify project euler problem 31

I was thinking about Project Euler #31 yesterday, quoted below: In England the currency is made up of pound, £, and pence, p, and there are eight coins in general circulation: 1p, 2p, 5p, ...
1
vote
1answer
257 views

Algorithm to find greatest significant digit of long integer

I'm doing a project euler problem (http://projecteuler.net/problem=40) that requires iteration of each digit of a set of increasing integers, in order. I solved it by converting each integer to a ...
3
votes
3answers
11k views

Largest prime factor of 600851475143 [duplicate]

I'm trying to use a program to find the largest prime factor of 600851475143. This is for Project Euler here: http://projecteuler.net/problem=3 I first attempted this with the code that goes through ...
3
votes
4answers
1k views

The longest sum of consecutive primes that add to a prime less than 1,000,000

In Project Euler problem $50,$ the goal is to find the longest sum of consecutive primes that add to a prime less than $1,000,000. $ I have an efficient algorithm to generate a set of primes ...
1
vote
1answer
262 views

Algorithm for generating an ordered list of pair products

For problem 4 in the euler project part of the assignment is to generate a list of products of 3-digit numbers. The easy way is to just do a cartesian product (I think it's called), and after that ...
2
votes
1answer
600 views

Finding all possible paths from one corner to the other on a grid, without backtracking

Me again "new to maths guy". Please tell me if the substance of my questions are not a good fit for the site. I'm now onto Question 15 of Project Euler and it seems like there's some mathematical ...
2
votes
0answers
440 views

Counting couples having least common multiple less than a number

Let f(n) be the number of couples (x,y) with x and y positive integers, $x\leq y$ and the least common multiple of x and y equal to n. Let g be the summatory function of f, i.e.: $g(n) = ...
2
votes
0answers
258 views

Bell-like recurrence

Let $$A(n)=\sum_{k=0}^{n-1}\binom{n}{k}A(k)+n!,\quad A(0)=1$$ $$B(n)=\sum_{k=0}^{n-1}\binom{n}{k}B(k)-n!-n!\sum_{k=1}^{n}\frac{1}{k!},\quad B(0)=-1.$$ I'm interested in computing $S(n)=A(n)+B(n)$ ...
0
votes
2answers
176 views

What is wrong with my algorithm (finding if the origin is within a triangle's interior)?

I am working on Project Euler Problem 102 and I thought I had a solution, but it seems I do not. Now, don't give me the solution. I know I'm on the right track. What I want to know is why my method ...
4
votes
0answers
661 views

Project Euler Problem 338

I'm stuck on Project Euler problem 338. This is a cross post from StackOverflow where I initially posted, however, it was suggested that I post it here too since the problem mostly relies on math. The ...