a(n) = 8*n^2 + 3*n + 1.

Terms

a(0) =1a(1) =12a(2) =39a(3) =82a(4) =141a(5) =216a(6) =307a(7) =414a(8) =537a(9) =676a(10) =831a(11) =1002a(12) =1189a(13) =1392a(14) =1611a(15) =1846a(16) =2097a(17) =2364a(18) =2647a(19) =2946a(20) =3261a(21) =3592a(22) =3939a(23) =4302a(24) =4681a(25) =5076a(26) =5487a(27) =5914a(28) =6357a(29) =6816