a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(7*k,k) / (6*k + 1).

A346667

a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(7*k,k) / (6*k + 1).

Terms

    a(0) =1a(1) =0a(2) =6a(3) =51a(4) =578a(5) =7011a(6) =89931a(7) =1198798a(8) =16445122a(9) =230643888a(10) =3292247673a(11) =47672499727a(12) =698569117499

External references