a(n) = 7^n - n^10.

Terms

a(0) =1a(1) =6a(2) =-975a(3) =-58706a(4) =-1046175a(5) =-9748818a(6) =-60348527a(7) =-281651706a(8) =-1067977023a(9) =-3446430794a(10) =-9717524751a(11) =-23960097858a(12) =-48076077023a(13) =-40969481442a(14) =388968417873