a(n) = (6*n)^6.

Terms

a(0) =0a(1) =46656a(2) =2985984a(3) =34012224a(4) =191102976a(5) =729000000a(6) =2176782336a(7) =5489031744a(8) =12230590464a(9) =24794911296a(10) =46656000000a(11) =82653950016a(12) =139314069504a(13) =225199600704a(14) =351298031616a(15) =531441000000a(16) =782757789696