Number of distinct lines through the origin in 3-dimensional cube of side length n.

Terms

a(0) =0a(1) =7a(2) =19a(3) =49a(4) =91a(5) =175a(6) =253a(7) =415a(8) =571a(9) =805a(10) =1033a(11) =1423a(12) =1723a(13) =2263a(14) =2713a(15) =3313a(16) =3913a(17) =4825a(18) =5491a(19) =6625a(20) =7513a(21) =8701a(22) =9811a(23) =11461a(24) =12637a(25) =14497a(26) =16045a(27) =18043a(28) =19807a(29) =22411