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A158268
a(n) = coefficient of x^n in the (2^(n-1))-th iteration of x*C(x) where C(x) is the Catalan function (A000108), for n>=1.
1
1, 2, 20, 684, 84864, 40783952, 78562790592, 613738473236928, 19459342629747109248, 2496653806284295319455488, 1291725241770954532057108070400, 2687434858858114549619735481969223680
OFFSET
1,2
PROG
(PARI) {a(n)=local(G=serreverse(x-x^2+O(x^(n+2)))); for(i=2, n, G=subst(G, x, G)); polcoeff(G, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 28 2009
STATUS
approved