Numbers of the form (3^j + 9^k)/2, for j and k >= 0.

Terms

a(0) =1a(1) =2a(2) =5a(3) =6a(4) =9a(5) =14a(6) =18a(7) =41a(8) =42a(9) =45a(10) =54a(11) =81a(12) =122a(13) =126a(14) =162a(15) =365a(16) =366a(17) =369a(18) =378a(19) =405a(20) =486a(21) =729a(22) =1094a(23) =1098a(24) =1134a(25) =1458a(26) =3281a(27) =3282a(28) =3285a(29) =3294