a(n) = 16*n^2 - n.

Terms

a(0) =15a(1) =62a(2) =141a(3) =252a(4) =395a(5) =570a(6) =777a(7) =1016a(8) =1287a(9) =1590a(10) =1925a(11) =2292a(12) =2691a(13) =3122a(14) =3585a(15) =4080a(16) =4607a(17) =5166a(18) =5757a(19) =6380a(20) =7035a(21) =7722a(22) =8441a(23) =9192a(24) =9975a(25) =10790a(26) =11637a(27) =12516a(28) =13427a(29) =14370