a(n) = binomial(8*n, n-8).A004389a(n) = binomial(8*n, n-8).Terms a(0) =1a(1) =72a(2) =3160a(3) =109736a(4) =3321960a(5) =91962520a(6) =2392407864a(7) =59487568920External referencesoeis: A004389