Number of points in N^n of norm <= 5.

Terms

a(0) =1a(1) =6a(2) =26a(3) =99a(4) =357a(5) =1203a(6) =3819a(7) =11496a(8) =33044a(9) =91067a(10) =241283a(11) =616618a(12) =1525908a(13) =3670422a(14) =8609234a(15) =19739642a(16) =44323092a(17) =97594520a(18) =210952363a(19) =448015366a(20) =935625977a(21) =1922870258a(22) =3891946458a(23) =7763818914a(24) =15275110988a(25) =29660831057