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

Terms

a(0) =64a(1) =46656a(2) =1000000a(3) =7529536a(4) =34012224a(5) =113379904a(6) =308915776a(7) =729000000a(8) =1544804416a(9) =3010936384a(10) =5489031744a(11) =9474296896a(12) =15625000000a(13) =24794911296a(14) =38068692544a(15) =56800235584a(16) =82653950016a(17) =117649000000a(18) =164206490176a(19) =225199600704a(20) =304006671424a(21) =404567235136a(22) =531441000000