5*n^2 + 4*n - 15.

Terms

a(0) =-6a(1) =13a(2) =42a(3) =81a(4) =130a(5) =189a(6) =258a(7) =337a(8) =426a(9) =525a(10) =634a(11) =753a(12) =882a(13) =1021a(14) =1170a(15) =1329a(16) =1498a(17) =1677a(18) =1866a(19) =2065a(20) =2274a(21) =2493a(22) =2722a(23) =2961a(24) =3210a(25) =3469a(26) =3738a(27) =4017a(28) =4306a(29) =4605