Number of line segments connecting exactly 9 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) =0a(8) =20a(9) =48a(10) =84a(11) =128a(12) =180a(13) =240a(14) =308a(15) =384a(16) =504a(17) =640a(18) =792a(19) =960a(20) =1144a(21) =1344a(22) =1560a(23) =1792a(24) =2144a(25) =2528a(26) =2944a(27) =3392a(28) =3872a(29) =4384