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

Terms

a(0) =1a(1) =3a(2) =15a(3) =54a(4) =201a(5) =672a(6) =2268a(7) =7266a(8) =23208a(9) =72414a(10) =224652a(11) =688929a(12) =2103975a(13) =6386907a(14) =19337091a(15) =58367817a(16) =175905741a(17) =529331190a(18) =1591515297a(19) =4781575074a(20) =14359673454a(21) =43108645230a(22) =129387584991a(23) =388283978589