a(n) = (4n + 3)^2.

Terms

a(0) =9a(1) =49a(2) =121a(3) =225a(4) =361a(5) =529a(6) =729a(7) =961a(8) =1225a(9) =1521a(10) =1849a(11) =2209a(12) =2601a(13) =3025a(14) =3481a(15) =3969a(16) =4489a(17) =5041a(18) =5625a(19) =6241a(20) =6889a(21) =7569a(22) =8281a(23) =9025a(24) =9801a(25) =10609a(26) =11449a(27) =12321a(28) =13225a(29) =14161