Number of collinear point 6-tuples in an n X n cubical grid.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =14a(6) =116a(7) =536a(8) =1824a(9) =5100a(10) =12432a(11) =27248a(12) =55148a(13) =104282a(14) =187120a(15) =320244a(16) =527976a(17) =840276a(18) =1300944a(19) =1959780a(20) =2888920a(21) =4168470a(22) =5910540a(23) =8233080a(24) =11310640a(25) =15309580a(26) =20477040a(27) =27057280a(28) =35393500a(29) =45803810