Number of line segments connecting exactly 8 points in an n x n grid of points.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =18a(8) =44a(9) =78a(10) =120a(11) =170a(12) =228a(13) =294a(14) =400a(15) =522a(16) =660a(17) =814a(18) =984a(19) =1170a(20) =1372a(21) =1682a(22) =2024a(23) =2398a(24) =2804a(25) =3242a(26) =3712a(27) =4214a(28) =4868a(29) =5570