Number of points in N^n of norm <= 9.

Terms

a(0) =1a(1) =10a(2) =73a(3) =486a(4) =2907a(5) =15930a(6) =81586a(7) =394251a(8) =1807754a(9) =7903501a(10) =33107532a(11) =133503791a(12) =520255432a(13) =1965535471a(14) =7218099342a(15) =25820149509a(16) =90120974981a(17) =307356231936