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

Terms

a(0) =1a(1) =0a(2) =-2a(3) =24a(4) =382a(5) =3480a(6) =26398a(7) =183624a(8) =1217662a(9) =7844280a(10) =49595998a(11) =309603624a(12) =1915345342a(13) =11771312280a(14) =71987479198a(15) =438579414024