a(n) = (5*n + 4)^2.

Terms

a(0) =16a(1) =81a(2) =196a(3) =361a(4) =576a(5) =841a(6) =1156a(7) =1521a(8) =1936a(9) =2401a(10) =2916a(11) =3481a(12) =4096a(13) =4761a(14) =5476a(15) =6241a(16) =7056a(17) =7921a(18) =8836a(19) =9801a(20) =10816a(21) =11881a(22) =12996a(23) =14161a(24) =15376a(25) =16641a(26) =17956a(27) =19321a(28) =20736a(29) =22201