A048983 As n runs through composite numbers, a(n) = number of composite d < n such that GCD(d,n) = 1.

0, 0, 0, 2, 1, 0, 1, 3, 2, 0, 1, 5, 3, 0, 11, 4, 9, 4, 0, 5, 10, 6, 14, 2, 7, 13, 5, 1, 7, 11, 9, 2, 27, 6, 18, 10, 3, 25, 9, 21, 13, 1, 13, 19, 14, 31, 4, 14, 26, 7, 5, 16, 20, 16, 40, 5, 11, 32, 19, 3, 42, 20, 34, 18, 2, 49, 21, 37, 23, 49, 9, 18