Number of ordered quintuples (a,b,c,d,e), -n <= a,b,c,d,e <= n, such that a+b+c+d+e = 0.

Terms

a(0) =1a(1) =51a(2) =381a(3) =1451a(4) =3951a(5) =8801a(6) =17151a(7) =30381a(8) =50101a(9) =78151a(10) =116601a(11) =167751a(12) =234131a(13) =318501a(14) =423851a(15) =553401a(16) =710601a(17) =899131a(18) =1122901a(19) =1386051a(20) =1692951a(21) =2048201a(22) =2456631a(23) =2923301a(24) =3453501a(25) =4052751a(26) =4726801a(27) =5481631a(28) =6323451a(29) =7258701