A109831 Greatest number of primes < prime(n) forming an arithmetic progression such that also prime(n) is a term.

1, 1, 2, 2, 1, 2, 2, 3, 4, 2, 1, 3, 3, 2, 4, 3, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 3, 2, 3, 4, 4, 2, 3, 3, 3, 5, 3, 3, 4, 2, 3, 3, 3, 4, 3, 2, 3, 4, 3, 3, 3, 3, 4, 5, 3, 3, 4, 2, 3, 4, 4, 3, 5, 3, 3, 3, 2, 3, 3, 5, 3, 3, 4, 2, 3, 4, 4, 3, 3, 3, 4, 3, 3, 3, 4, 4, 3, 3, 5, 3, 4, 3, 3, 2, 3, 5, 4, 3, 3, 3, 2, 3