Project Euler — Problem 206 Solution

Problem

Find the unique positive integer whose square has the form 1_2_3_4_5_6_7_8_9_0,

where each “_” is a single digit.

Solution

Project Euler — Problem 67 Solution

Problem

By starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.

That is, 3 + 7 + 4 + 9 = 23.

Project Euler — Problem 19 Solution

Problem

You are given the following information, but you may prefer to do some research for yourself.

• 1 Jan 1900 was a Monday.
• Thirty days has September, April, June and November. All…

Project Euler — Problem 7 Solution

Problem

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 10001st prime number?

Solution

Project Euler — Problem 30 Solution

Problem

Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:

1634 = 14 + 64 + 34 + 44

8208 = 84 + 24 + 04 + 84

Project Euler — Problem 12 Solution

Problem

The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:

1, 3, 6, 10, 15, 21, 28, 36…

Project Euler — Problem 40 Solution

Problem

An irrational decimal fraction is created by concatenating the positive integers:

0.123456789101112131415161718192021…

It can be seen that the 12th digit of the fractional part…

Project Euler — Problem 27 Solution

Problem

Euler published the remarkable quadratic formula:

n² + n + 41

It turns out that the formula will produce 40 primes for the consecutive values n = 0 to 39. However, when n = 40…

Project Euler — Problem 92 Solution

Problem

A number chain is created by continuously adding the square of the digits in a number to form a new number until it has been seen before.

For example,

Therefore any chain that…