Number of points in N^n of norm <= 7.

Terms

a(0) =1a(1) =8a(2) =45a(3) =239a(4) =1154a(5) =5139a(6) =21374a(7) =83877a(8) =312913a(9) =1115334a(10) =3813001a(11) =12556041a(12) =39993741a(13) =123663399a(14) =372232239a(15) =1093036739a(16) =3136328324a(17) =8805588398a(18) =24218635622a(19) =65321490327a(20) =172947226965a(21) =449923333530