Expansion of Product_{i>=1, j>=1, k>=1, l>=1} (1 + x^(i*j*k*l))/(1 - x^(i*j*k*l)).

Terms

a(0) =1a(1) =2a(2) =10a(3) =26a(4) =86a(5) =210a(6) =594a(7) =1394a(8) =3530a(9) =8006a(10) =18842a(11) =41258a(12) =92190a(13) =195714a(14) =419538a(15) =867050a(16) =1797568a(17) =3625758a(18) =7311382a(19) =14431294a(20) =28416514a(21) =55010142a(22) =106101558a(23) =201814518a(24) =382213566a(25) =715473554a(26) =1333083950a(27) =2459265058a(28) =4515151234a(29) =8218572030