a(n) = 4th Chebyshev polynomial (second kind) evaluated at 2^n.

A020541

a(n) = 4th Chebyshev polynomial (second kind) evaluated at 2^n.

Terms

    a(0) =5a(1) =209a(2) =3905a(3) =64769a(4) =1045505a(5) =16764929a(6) =268386305a(7) =4294770689a(8) =68718690305

External references