OCR Coding Challenges - Solutions

As a background task, I've started work on possible solutions to the OCR Coding Challenges. Remember that my solution is just one of a number of possible solutions, and I don't claim that it's necessarily the best one.

No. Link
1 Factorial Finder - Iteration
Factorial Finder - Recursion
3 Thief!
4 Classification
7 Credit Card Validator
9 Happy Numbers
13 Caesar Cipher
15 Pangrams
16 Kaprekar
20 Palindrome
36 Triangulate
37 Fizz Buzz