Binomial coefficient C(7n,n-1).

A004369

Binomial coefficient C(7n,n-1).

Terms

    a(0) =1a(1) =14a(2) =210a(3) =3276a(4) =52360a(5) =850668a(6) =13983816a(7) =231917400a(8) =3872894697a(9) =65033528560

External references