Least k such that base 3 representation of n begins at s(k), where s=A030351.

Terms

a(0) =1a(1) =4a(2) =1a(3) =5a(4) =3a(5) =10a(6) =4a(7) =16a(8) =7a(9) =1a(10) =33a(11) =6a(12) =5a(13) =20a(14) =21a(15) =3a(16) =15a(17) =49a(18) =10a(19) =44a(20) =35a(21) =4a(22) =17a(23) =43a(24) =16a(25) =70a(26) =39a(27) =12a(28) =7a(29) =31