A024870 a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = A023531.

2, 0, 0, 2, 3, 4, 5, 2, 3, 4, 5, 6, 9, 11, 13, 5, 6, 7, 10, 12, 14, 16, 18, 20, 22, 11, 13, 15, 17, 19, 21, 23, 25, 29, 32, 35, 38, 20, 22, 24, 26, 28, 32, 35, 38, 41, 44, 47, 50, 53, 56, 31, 35, 38, 41, 44, 47, 50, 53, 56, 59, 62, 65, 70, 74, 78, 82, 50, 53, 56, 59, 62, 65, 68, 71, 76, 80, 84, 88