Numbers of the form 3^i*5^j with i, j >= 0.

Terms

a(0) =1a(1) =3a(2) =5a(3) =9a(4) =15a(5) =25a(6) =27a(7) =45a(8) =75a(9) =81a(10) =125a(11) =135a(12) =225a(13) =243a(14) =375a(15) =405a(16) =625a(17) =675a(18) =729a(19) =1125a(20) =1215a(21) =1875a(22) =2025a(23) =2187a(24) =3125a(25) =3375a(26) =3645a(27) =5625a(28) =6075a(29) =6561