Here, I'll collect my on-line programs and some pages about my favourite books. I have just started, so for the moment on-line there are:
On-line detection of more than 150 properties of numbers up to 15 digits. Check today date written as a number: 11222019
An on-line anagram solver to find anagrams of words or phrases and help you finding words for Scrabble.
Cryptarithms: Create and Solve
An on-line program to play with Cryptarithms and Alphametics.
Ask Dr. Matrix
An on-line numerologist who will find connections between numbers and words
A fascinating problem involving polyominoes.
Livio Zucca's pages (a mirror)
Livio's pages are full of wonderful puzzles, results and pictures about polyominoes and similar oddities.