Expansion of Product_{k>=1} ((1 + x^k) * (1 + 2*x^k)).

Terms

a(0) =1a(1) =3a(2) =5a(3) =12a(4) =20a(5) =33a(6) =60a(7) =93a(8) =144a(9) =222a(10) =340a(11) =498a(12) =729a(13) =1050a(14) =1486a(15) =2115a(16) =2946a(17) =4068a(18) =5592a(19) =7608a(20) =10278a(21) =13854a(22) =18483a(23) =24528a(24) =32426a(25) =42594a(26) =55677a(27) =72498a(28) =94008a(29) =121290