a(n) = T(n, 3*n), where T(n, x) is the Chebyshev polynomial of the first kind.

A349072

a(n) = T(n, 3*n), where T(n, x) is the Chebyshev polynomial of the first kind.

Terms

    a(0) =1a(1) =3a(2) =71a(3) =2889a(4) =164737a(5) =12082575a(6) =1083358151a(7) =114812765781

External references