a1exkh/myprojecteulersolutions

my code of solutions for project Euler project

About this repo:

This repo contains my JavaScript code solutions for project Euler.

List of tasks:

Problem #1.

Multiples of 3 and 5. Find the sum of all the multiples of 3 or 5 below 1000.

Problem #2.

Even Fibonacci numbers. By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

Problem #3.

Largest prime factor. The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ?

Problem #4.

Largest palindrome product. A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99. Find the largest palindrome made from the product of two 3-digit numbers.

Problem #5.

Smallest multiple. 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

Problem #6.

Sum square difference. Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.

Problem #7.

10001st prime. By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. What is the 10 001st prime number?

Problem #8.

Largest product in a series. Find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product?

Problem #9.

Special Pythagorean triplet. There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product abc.

Problem #10.

Summation of primes. Find the sum of all the primes below two million.

Problem #11.

Largest product in a grid. What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?

Problem #12.

Highly divisible triangular number. What is the value of the first triangle number to have over five hundred divisors?

Problem 13.

Large Sum Work out the first ten digits of the sum of the following one-hundred 50-digit numbers.

Problem #14.

Longest Collatz sequence. It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. Although it has not been proved yet (Collatz Problem), it is thought that all starting numbers finish at 1. Which starting number, under one million, produces the longest chain? NOTE: Once the chain starts the terms are allowed to go above one million.

Problem #18.

Maximum path sum. Find the maximum total from top to bottom of the triangle below:

Problem #21.

Amicable numbers. Evaluate the sum of all the amicable numbers under 10000.

Problem #22.

Names scores. For example, when the list is sorted into alphabetical order, COLIN, which is worth 3 + 15 + 12 + 9 + 14 = 53, is the 938th name in the list. So, COLIN would obtain a score of 938 × 53 = 49714. What is the total of all the name scores in the file?