a(n) = (11n+1)^6.

Terms

a(0) =1a(1) =2985984a(2) =148035889a(3) =1544804416a(4) =8303765625a(5) =30840979456a(6) =90458382169a(7) =225199600704a(8) =496981290961a(9) =1000000000000