a(n) = 2^n-n^9.

Terms

a(0) =1a(1) =1a(2) =-508a(3) =-19675a(4) =-262128a(5) =-1953093a(6) =-10077632a(7) =-40353479a(8) =-134217472a(9) =-387419977a(10) =-999998976a(11) =-2357945643a(12) =-5159776256a(13) =-10604491181a(14) =-20661030400a(15) =-38443326607a(16) =-68719411200a(17) =-118587745425a(18) =-198359028224a(19) =-322687173491a(20) =-511998951424a(21) =-794277949429