A135679 a(n) = n if n = 1 or if n is prime. Otherwise, a(n) = 2 if n is even and a(n) = 3 if n is odd.

1, 2, 3, 2, 5, 2, 7, 2, 3, 2, 11, 2, 13, 2, 3, 2, 17, 2, 19, 2, 3, 2, 23, 2, 3, 2, 3, 2, 29, 2, 31, 2, 3, 2, 3, 2, 37, 2, 3, 2, 41, 2, 43, 2, 3, 2, 47, 2, 3, 2, 3, 2, 53, 2, 3, 2, 3, 2, 59, 2, 61, 2, 3, 2, 3, 2, 67, 2, 3, 2, 71, 2, 73