a(n) = 8*n^2 + 4*n + 1.

Terms

a(0) =1a(1) =13a(2) =41a(3) =85a(4) =145a(5) =221a(6) =313a(7) =421a(8) =545a(9) =685a(10) =841a(11) =1013a(12) =1201a(13) =1405a(14) =1625a(15) =1861a(16) =2113a(17) =2381a(18) =2665a(19) =2965a(20) =3281a(21) =3613a(22) =3961a(23) =4325a(24) =4705a(25) =5101a(26) =5513a(27) =5941a(28) =6385a(29) =6845