a(n) = 2*n^2 + 11*n + 12.

Terms

a(0) =3a(1) =12a(2) =25a(3) =42a(4) =63a(5) =88a(6) =117a(7) =150a(8) =187a(9) =228a(10) =273a(11) =322a(12) =375a(13) =432a(14) =493a(15) =558a(16) =627a(17) =700a(18) =777a(19) =858a(20) =943a(21) =1032a(22) =1125a(23) =1222a(24) =1323a(25) =1428a(26) =1537a(27) =1650a(28) =1767a(29) =1888