Expansion of Product_{k>=1} (1 + 3*x^k)^k.

Terms

a(0) =1a(1) =3a(2) =6a(3) =27a(4) =48a(5) =132a(6) =324a(7) =651a(8) =1491a(9) =3078a(10) =6447a(11) =12795a(12) =25839a(13) =50088a(14) =96099a(15) =184491a(16) =343920a(17) =640545a(18) =1173609a(19) =2138403a(20) =3850584a(21) =6882354a(22) =12186336a(23) =21423660a(24) =37421757a(25) =64816608a(26) =111637392a(27) =190976859a(28) =324868530a(29) =549265290