Index of 3^n within the sequence of the numbers of the form 3^i * 10^j.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =7a(5) =10a(6) =13a(7) =17a(8) =21a(9) =26a(10) =31a(11) =37a(12) =43a(13) =50a(14) =57a(15) =65a(16) =73a(17) =82a(18) =91a(19) =101a(20) =111a(21) =122a(22) =133a(23) =144a(24) =156a(25) =168a(26) =181a(27) =194a(28) =208a(29) =222