a(n) = n^8 - n^7 + n^5 - n^4 + n^3 - n + 1.

Terms

a(0) =1a(1) =1a(2) =151a(3) =4561a(4) =49981a(5) =315121a(6) =1406371a(7) =4956001a(8) =14709241a(9) =38316961a(10) =90090991a(11) =195019441a(12) =394379701a(13) =753327121a(14) =1370877691a(15) =2392743361a(16) =4027518961a(17) =6566760001a(18) =10409530951a(19) =16092043921a(20) =24323047981a(21) =36025669681a(22) =52386445651a(23) =74912328481a(24) =105496487401a(25) =146493765601