Numbers of the form (3^i)*(13^j).

Terms

a(0) =1a(1) =3a(2) =9a(3) =13a(4) =27a(5) =39a(6) =81a(7) =117a(8) =169a(9) =243a(10) =351a(11) =507a(12) =729a(13) =1053a(14) =1521a(15) =2187a(16) =2197a(17) =3159a(18) =4563a(19) =6561a(20) =6591a(21) =9477a(22) =13689a(23) =19683a(24) =19773a(25) =28431a(26) =28561a(27) =41067a(28) =59049a(29) =59319