a(n) = U(2*n, n), where U(n, x) is the Chebyshev polynomial of the second kind.

A349073

a(n) = U(2*n, n), where U(n, x) is the Chebyshev polynomial of the second kind.

Terms

    a(0) =1a(1) =3a(2) =209a(3) =40391a(4) =15003009a(5) =9127651499

External references