a(n)=least such that base 3 representation of n begins at s(k), where s=A030353.

Terms

a(0) =1a(1) =5a(2) =2a(3) =1a(4) =4a(5) =18a(6) =6a(7) =5a(8) =8a(9) =2a(10) =11a(11) =1a(12) =14a(13) =16a(14) =17a(15) =25a(16) =4a(17) =72a(18) =18a(19) =76a(20) =26a(21) =6a(22) =29a(23) =22a(24) =5a(25) =21a(26) =35a(27) =8a(28) =39a(29) =168