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Project Euler 1 Mystery Cache

Hidden : 10/9/2018
Difficulty:
1.5 out of 5
Terrain:
1.5 out of 5

Size: Size:   other (other)

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Geocache Description:


The published coordinates are for Lancaster University's maths and stats centre -- you will not find the cache there. However, Leonhard Euler was a Swiss mathematician, physicist, astronomer, logician and engineer​.

Acknowledgements

This cache was inspired by Project Euler and by a very similar series of caches in Cambridge by mjouk.

General notes

  • To solve Project Euler puzzles, you will probably have to write a computer program.
  • Many of the containers are small, and contain neither pen nor pencil.
  • Caches are placed around Lancaster and the surrounding areas. Many of the caches are in busy or residential areas.

There are currently 7 caches in the Lancaster series.
Find them all: 1, 2, 3, 4, 5, 6, 7


The puzzle​

If we list all the natural numbers below 10 that are divisible by 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.

Define f(n) as the sum of the multiples of 3 and 5 which are less than n. Thus we can write:
f(10) = 23.

N = f(4812) - f(52) - f(25)

W = f(1030) + f(28) + f(8)

 

Project Euler Hall of Fame

For the complete Hall of Fame, visit: http://www.sclinch.com/geocaching/euler.html

Additional Hints (Decrypt)

Zntargvp.

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)