A073893 a(10k) = 0 and if n is not a multiple of 10 then a(n) is the smallest positive integer such that the concatenation of the first n terms is a multiple of n.

1, 2, 3, 2, 5, 2, 5, 6, 1, 0, 8, 4, 9, 4, 5, 6, 25, 2, 15, 0, 15, 10, 28, 16, 25, 16, 28, 16, 13, 0, 14, 4, 22, 36, 5, 16, 35, 14, 47, 0, 16, 8, 42, 28, 35, 18, 49, 44, 27, 0, 42, 4, 26, 6, 45, 52, 53, 38, 62, 0, 44, 50, 25, 28, 15, 32, 43, 72, 29, 0, 61, 44, 45, 8, 25, 56, 82, 84, 85, 0