A031099 a(n)=least k such that base 9 representation of n begins at s(k), where s=A031098.

7, 6, 5, 4, 3, 2, 1, 10, 7, 131, 114, 96, 78, 60, 42, 24, 117, 115, 6, 111, 94, 76, 58, 40, 22, 99, 97, 95, 5, 91, 74, 56, 38, 20, 81, 79, 77, 75, 4, 71, 54, 36, 18, 63, 61, 59, 57, 55, 3, 51, 34, 16, 45, 43, 41, 39, 37, 35, 2, 31, 14, 27, 25, 23