a(n) = Sum_{k=0..2n} C(2n,k)*A027907(n,k) where A027907 is the triangle of trinomial coefficients.

A168595

a(n) = Sum_{k=0..2n} C(2n,k)*A027907(n,k) where A027907 is the triangle of trinomial coefficients.

Terms

    a(0) =1a(1) =4a(2) =36a(3) =358a(4) =3748a(5) =40404a(6) =443886a(7) =4941654a(8) =55555236a(9) =629285416a(10) =7170731236a(11) =82108083204a(12) =943960439086

External references