a(n) = 15*n^2 + 9*n + 1.

Terms

a(0) =1a(1) =25a(2) =79a(3) =163a(4) =277a(5) =421a(6) =595a(7) =799a(8) =1033a(9) =1297a(10) =1591a(11) =1915a(12) =2269a(13) =2653a(14) =3067a(15) =3511a(16) =3985a(17) =4489a(18) =5023a(19) =5587a(20) =6181a(21) =6805a(22) =7459a(23) =8143a(24) =8857a(25) =9601a(26) =10375a(27) =11179a(28) =12013a(29) =12877