Index of 6^n within the sequence of the numbers of the form 3^i*6^j.

Terms

a(0) =1a(1) =3a(2) =7a(3) =12a(4) =19a(5) =28a(6) =38a(7) =50a(8) =64a(9) =79a(10) =96a(11) =114a(12) =134a(13) =156a(14) =179a(15) =204a(16) =231a(17) =259a(18) =289a(19) =320a(20) =353a(21) =388a(22) =424a(23) =462a(24) =502a(25) =543a(26) =586a(27) =631a(28) =677a(29) =725