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

Terms

a(0) =1a(1) =6a(2) =30a(3) =128a(4) =486a(5) =1704a(6) =5604a(7) =17484a(8) =52206a(9) =150118a(10) =417696a(11) =1128984a(12) =2973476a(13) =7650720a(14) =19272432a(15) =47616568a(16) =115570014a(17) =275921460a(18) =648771802a(19) =1503889488a(20) =3439990344a(21) =7770915816a(22) =17349229908a(23) =38306180052a(24) =83694778556a(25) =181052778078a(26) =387976101432a(27) =823939048560