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

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =1a(4) =-2a(5) =-3a(6) =7a(7) =-4a(8) =-1a(9) =20a(10) =-9a(11) =-15a(12) =45a(13) =-39a(14) =-38a(15) =95a(16) =-81a(17) =-99a(18) =244a(19) =-196a(20) =-188a(21) =538a(22) =-371a(23) =-421a(24) =1256a(25) =-823a(26) =-820a(27) =2575a(28) =-1672a(29) =-1904