Number of lines through at least 2 points of a 7 X n grid of points.

Terms

a(0) =0a(1) =1a(2) =51a(3) =100a(4) =181a(5) =274a(6) =405a(7) =536a(8) =709a(9) =894a(10) =1111a(11) =1330a(12) =1591a(13) =1858a(14) =2167a(15) =2482a(16) =2825a(17) =3180a(18) =3577a(19) =3974a(20) =4413a(21) =4860a(22) =5339a(23) =5824a(24) =6351a(25) =6884a(26) =7455a(27) =8032a(28) =8641a(29) =9262