Number of points of norm <= n in cubic lattice.

Terms

a(0) =1a(1) =7a(2) =33a(3) =123a(4) =257a(5) =515a(6) =925a(7) =1419a(8) =2109a(9) =3071a(10) =4169a(11) =5575a(12) =7153a(13) =9171a(14) =11513a(15) =14147a(16) =17077a(17) =20479a(18) =24405a(19) =28671a(20) =33401a(21) =38911a(22) =44473a(23) =50883a(24) =57777a(25) =65267a(26) =73525a(27) =82519a(28) =91965a(29) =101943