a(n) = 6^n - 5^n - 4^n - 3^n - 2^n.

Terms

a(0) =-8a(1) =-18a(2) =-8a(3) =318a(4) =3352a(5) =26142a(6) =183112a(7) =1216638a(8) =7842232a(9) =49591902a(10) =309595432a(11) =1915328958a(12) =11771279512a(13) =71987413662a(14) =438579282952