a(n) = 7^n-6^n-5^n-4^n-3^n-2^n-1.

Terms

a(0) =-5a(1) =-14a(2) =-42a(3) =-98a(4) =126a(5) =4606a(6) =50478a(7) =446782a(8) =3622206a(9) =28040446a(10) =211134798a(11) =1561328062a(12) =11403051486a(13) =82538901886a(14) =593482158318