a(n) = (-1)^n*hypergeom([-n, n], [1], 4).
A299507
a(n) = (-1)^n*hypergeom([-n, n], [1], 4).
Terms
- a(0) =1a(1) =3a(2) =33a(3) =387a(4) =4737a(5) =59523a(6) =761121a(7) =9854211a(8) =128772609a(9) =1694927619a(10) =22437369633a(11) =298419470979
External references
- oeis: A299507