a(n) = C(2^n + 2*n + 1, n)*(2^n + 1)/(2^n + 2*n + 1); a(n) = coefficient of x^n in Catalan(x)^(2^n+1).
A136551
a(n) = C(2^n + 2*n + 1, n)*(2^n + 1)/(2^n + 2*n + 1); a(n) = coefficient of x^n in Catalan(x)^(2^n+1).
Terms
- a(0) =1a(1) =3a(2) =20a(3) =273a(4) =8602a(5) =738738a(6) =200144100a(7) =188542438797
External references
- oeis: A136551