The Prime Game

Recursivity: The Prime Game

Ask a friend to write down a prime number. Bet them that you can always strike out 0 or more digits to get one of the following 26 primes:

2, 3, 5, 7, 11, 19, 41, 61, 89, 409, 449, 499, 881, 991, 6469, 6949, 9001, 9049, 9649, 9949, 60649, 666649, 946669, 60000049, 66000049, 66600049

A very cool bit of mathematics.

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