a(n) = number of triangles that can be formed from the points of a 3 X n grid.

Terms

a(0) =0a(1) =18a(2) =76a(3) =200a(4) =412a(5) =738a(6) =1200a(7) =1824a(8) =2632a(9) =3650a(10) =4900a(11) =6408a(12) =8196a(13) =10290a(14) =12712a(15) =15488a(16) =18640a(17) =22194a(18) =26172a(19) =30600a(20) =35500a(21) =40898a(22) =46816a(23) =53280a(24) =60312a(25) =67938a(26) =76180a(27) =85064a(28) =94612a(29) =104850