a(n) = n^10*(n + 1)/2.

Terms

a(0) =0a(1) =1a(2) =1536a(3) =118098a(4) =2621440a(5) =29296875a(6) =211631616a(7) =1129900996a(8) =4831838208a(9) =17433922005a(10) =55000000000a(11) =155624547606a(12) =402462867456a(13) =965009442943