a(n) is the numerator of 6 * Sum_{k=0..n} ((k+1)/(n-k+1)^2) * (Catalan(k)/(2^(2*k+1)))^2.

A281070

a(n) is the numerator of 6 * Sum_{k=0..n} ((k+1)/(n-k+1)^2) * (Catalan(k)/(2^(2*k+1)))^2.

Terms

    a(0) =3a(1) =9a(2) =109a(3) =1037a(4) =91027a(5) =1540981a(6) =447810157a(7) =147053171a(8) =503445581741

External references