Expansion of Product_{k>=0} 1/(1-x^(3*k+1))^3.

Terms

a(0) =1a(1) =3a(2) =6a(3) =10a(4) =18a(5) =30a(6) =46a(7) =69a(8) =105a(9) =154a(10) =219a(11) =309a(12) =434a(13) =597a(14) =813a(15) =1100a(16) =1476a(17) =1959a(18) =2585a(19) =3387a(20) =4410a(21) =5709a(22) =7353a(23) =9414a(24) =12001a(25) =15231a(26) =19242a(27) =24205a(28) =30348a(29) =37902