a(n)=least k such that base 8 representation of n begins at s(k), where s=A031045.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =7a(7) =23a(8) =9a(9) =1a(10) =13a(11) =15a(12) =17a(13) =19a(14) =21a(15) =39a(16) =12a(17) =27a(18) =2a(19) =31a(20) =33a(21) =35a(22) =37a(23) =55a(24) =14a(25) =30a(26) =45a(27) =3a(28) =49a(29) =51