A031275 a(n)=least k such that the base 5 representation of n begins at s(k), where s=A031269.

1, 2, 3, 10, 4, 11, 1, 6, 13, 35, 15, 40, 2, 19, 29, 3, 7, 28, 9, 47, 10, 14, 88, 33, 95, 4, 149, 16, 142, 69, 11, 56, 52, 12, 57, 155, 82, 1, 37, 137, 215, 6, 27, 219, 77, 25, 13, 240, 237, 463, 35, 234, 131, 58, 15, 55, 232, 598, 156, 260, 119