a(n)=least k such that base 6 representation of n begins at s(k), where s=A030567.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =17a(6) =7a(7) =1a(8) =11a(9) =13a(10) =15a(11) =29a(12) =10a(13) =21a(14) =2a(15) =25a(16) =27a(17) =41a(18) =12a(19) =24a(20) =35a(21) =3a(22) =39a(23) =53a(24) =14a(25) =26a(26) =38a(27) =49a(28) =4a(29) =5