A Fibonacci concat prime is a prime number obtained by concatenating several first elements of the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, …). These numbers showed up in Evelyn Lamb’s tweet and got me interested, especially since I wanted to play with primality testing of big numbers in Haskell. (‘Fibonacci concat prime’ is a completely made up name; shout if you know the right one!)
Known trivial examples:
- 11 = 1 • 1
- 1123 = 1 • 1 • 2 • 3
I got curious if there were any other Fibonacci concat primes and wrote a generator in Haskell using this implementation of Miller-Rabin primality test.