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

Terms

a(0) =16a(1) =4096a(2) =38416a(3) =160000a(4) =456976a(5) =1048576a(6) =2085136a(7) =3748096a(8) =6250000a(9) =9834496a(10) =14776336a(11) =21381376a(12) =29986576a(13) =40960000a(14) =54700816a(15) =71639296a(16) =92236816a(17) =116985856a(18) =146410000a(19) =181063936a(20) =221533456a(21) =268435456a(22) =322417936a(23) =384160000a(24) =454371856a(25) =533794816a(26) =623201296