a(n) = hypergeom([-n, -n, n, n + 1], [1, 1, 1], 1).

A361878

a(n) = hypergeom([-n, -n, n, n + 1], [1, 1, 1], 1).

Terms

    a(0) =1a(1) =3a(2) =43a(3) =849a(4) =19371a(5) =480503a(6) =12587065a(7) =342634365a(8) =9596641195a(9) =274766987955

External references