a(n) = 4*n^2 - 6*n + 1.

Terms

a(0) =-1a(1) =5a(2) =19a(3) =41a(4) =71a(5) =109a(6) =155a(7) =209a(8) =271a(9) =341a(10) =419a(11) =505a(12) =599a(13) =701a(14) =811a(15) =929a(16) =1055a(17) =1189a(18) =1331a(19) =1481a(20) =1639a(21) =1805a(22) =1979a(23) =2161a(24) =2351a(25) =2549a(26) =2755a(27) =2969a(28) =3191a(29) =3421