Constant term in the expansion of (1 + x^3 + y^3 + z^3 + 1/(x*y*z))^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =121a(7) =841a(8) =3361a(9) =10081a(10) =25201a(11) =55441a(12) =194041a(13) =1287001a(14) =7927921a(15) =38438401a(16) =152312161a(17) =516079201a(18) =1627691521a(19) =5745472321a(20) =25999820401a(21) =133086258481a(22) =651284938921