Exploring mathematics through programming can be great fun and it can really help with understanding and implementing mathematical ideas generally. Here are some useful resources and links for coding mathematics:

Project Euler contains lots of great mathematical coding challenges.

Python coding in your browser at the Codecademy website.

WolframAlpha can answer many of your questions about mathematics.

Crash Course column in MEI's monthly maths magazine provides a introduction to Python coding applied to mathematics.

Further Pure with Technology, MEI's Further Mathematics unit in which you get to code!