a(n) = (8*n+6)^2.

Terms

a(0) =36a(1) =196a(2) =484a(3) =900a(4) =1444a(5) =2116a(6) =2916a(7) =3844a(8) =4900a(9) =6084a(10) =7396a(11) =8836a(12) =10404a(13) =12100a(14) =13924a(15) =15876a(16) =17956a(17) =20164a(18) =22500a(19) =24964a(20) =27556a(21) =30276a(22) =33124a(23) =36100a(24) =39204a(25) =42436a(26) =45796a(27) =49284a(28) =52900a(29) =56644