a(n) = 6^n - n^10.

Terms

a(0) =1a(1) =5a(2) =-988a(3) =-58833a(4) =-1047280a(5) =-9757849a(6) =-60419520a(7) =-282195313a(8) =-1072062208a(9) =-3476706705a(10) =-9939533824a(11) =-25574627545a(12) =-59740581888a(13) =-124797797833a(14) =-210890490880a(15) =-106465406049