Expansion of Product_{k>=0} 1/(1-x^(4*k+1))^3.

Terms

a(0) =1a(1) =3a(2) =6a(3) =10a(4) =15a(5) =24a(6) =37a(7) =54a(8) =75a(9) =103a(10) =144a(11) =198a(12) =265a(13) =348a(14) =456a(15) =599a(16) =777a(17) =993a(18) =1262a(19) =1602a(20) =2028a(21) =2543a(22) =3165a(23) =3930a(24) =4868a(25) =6003a(26) =7359a(27) =8991a(28) =10965a(29) =13329