Index of 9^n within the sequence of the numbers of the form 2^i*9^j.

Terms

a(0) =1a(1) =5a(2) =12a(3) =22a(4) =35a(5) =51a(6) =71a(7) =94a(8) =120a(9) =149a(10) =181a(11) =216a(12) =255a(13) =297a(14) =342a(15) =390a(16) =441a(17) =495a(18) =553a(19) =614a(20) =678a(21) =745a(22) =815a(23) =888a(24) =965a(25) =1045a(26) =1128a(27) =1214a(28) =1303a(29) =1395