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

Terms

a(0) =7a(1) =6a(2) =5a(3) =4a(4) =3a(5) =2a(6) =1a(7) =10a(8) =7a(9) =131a(10) =114a(11) =96a(12) =78a(13) =60a(14) =42a(15) =24a(16) =117a(17) =115a(18) =6a(19) =111a(20) =94a(21) =76a(22) =58a(23) =40a(24) =22a(25) =99a(26) =97a(27) =95a(28) =5a(29) =91