a(n) = 1 - n^9.

Terms

a(0) =1a(1) =0a(2) =-511a(3) =-19682a(4) =-262143a(5) =-1953124a(6) =-10077695a(7) =-40353606a(8) =-134217727a(9) =-387420488a(10) =-999999999a(11) =-2357947690a(12) =-5159780351a(13) =-10604499372a(14) =-20661046783a(15) =-38443359374a(16) =-68719476735a(17) =-118587876496a(18) =-198359290367