a(n) = (9*n + 6)^6.

Terms

a(0) =46656a(1) =11390625a(2) =191102976a(3) =1291467969a(4) =5489031744a(5) =17596287801a(6) =46656000000a(7) =107918163081a(8) =225199600704a(9) =433626201009a(10) =782757789696