Index of 8^n within the sequence of the numbers of the form 3^i*8^j (A025615).

Terms

a(0) =1a(1) =3a(2) =7a(3) =13a(4) =21a(5) =31a(6) =43a(7) =57a(8) =73a(9) =91a(10) =110a(11) =131a(12) =154a(13) =179a(14) =206a(15) =235a(16) =266a(17) =299a(18) =334a(19) =370a(20) =408a(21) =448a(22) =490a(23) =534a(24) =580a(25) =628a(26) =678a(27) =730a(28) =783a(29) =838