Number of collinear point-triples in an n X n grid.

Terms

a(0) =0a(1) =0a(2) =8a(3) =44a(4) =152a(5) =372a(6) =824a(7) =1544a(8) =2712a(9) =4448a(10) =6992a(11) =10332a(12) =15072a(13) =21012a(14) =28688a(15) =38520a(16) =50880a(17) =65480a(18) =83640a(19) =104676a(20) =130264a(21) =160556a(22) =195848a(23) =235600a(24) =282840a(25) =336384a(26) =397136a(27) =465876a(28) =544464a(29) =630684