A158269 a(n) = coefficient of x^n in the (2^n)-th iteration of x*C(x) where C(x) is the Catalan function (A000108), for n>=1.

1, 4, 72, 4760, 1196800, 1185344160, 4704904407424, 75251548566631296, 4850542035077717613312, 1257976093502471658023554560, 1310350352604009611135942297681920

Offset: 1

Author

Paul D. Hanna, Mar 28 2009

Keywords

• nonn

Crossrefs

Cf. A158268, A000108, A158825.

Programs

PARI

{a(n)=local(G=serreverse(x-x^2+O(x^(n+2))));for(i=2,n+1,G=subst(G,x,G));polcoeff(G,n)}