Number of sets of four points on an n X n grid (or geoboard), exactly three of which are collinear.

A189346

Number of sets of four points on an n X n grid (or geoboard), exactly three of which are collinear.

Terms

    a(0) =0a(1) =0a(2) =48a(3) =532a(4) =3088a(5) =11340a(6) =33824a(7) =83288a(8) =183344a(9) =364304a(10) =681872a(11) =1194100a(12) =1992976a(13) =3182332a(14) =4941360a(15) =7420640a(16) =10874720a(17) =15539952a(18) =21812720a(19) =30011924a(20) =40650368a(21) =54187196a(22) =71463440a(23) =92990296a(24) =119675712a(25) =152314920a(26) =192393872a(27) =240690060

External references