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 A156908 G.f.: A(x) = 1 + x*exp( Sum_{k>=1} [A(3^k*x) - 1]^k/k ). 2
 1, 1, 3, 72, 10899, 13775400, 185126087574, 25804839804745266, 34576186149297464460939, 431016348991655088520874274528, 49345807665910247245278532420622266770 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Conjectured to consist entirely of integers. LINKS EXAMPLE G.f.: A(x) = 1 + x + 3*x^2 + 72*x^3 + 10899*x^4 + 13775400*x^5 +... ... A(x) = 1 + x*exp( [A(3x)-1] + [A(9x)-1]^2/2 + [A(27x)-1]^3/3 +... ). PROG (PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1+x*exp(sum(k=1, n, (subst(A, x, 3^k*x+x*O(x^n))-1)^k/k))); polcoeff(A, n)} CROSSREFS Cf. A156907. Sequence in context: A332747 A202948 A213986 * A182517 A135866 A307925 Adjacent sequences:  A156905 A156906 A156907 * A156909 A156910 A156911 KEYWORD nonn AUTHOR Paul D. Hanna, Mar 04 2009 STATUS approved

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Last modified August 5 04:03 EDT 2021. Contains 346457 sequences. (Running on oeis4.)