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 A156907 G.f.: A(x) = 1 + x*exp( Sum_{k>=1} [A(2^k*x) - 1]^k/k ). 3

%I

%S 1,1,2,18,476,38358,11363548,15060027956,92500603618872,

%T 2483766272252845670,279689176516909339664044,

%U 129570236404446129260308225372,244562582019257683819447274838128648

%N G.f.: A(x) = 1 + x*exp( Sum_{k>=1} [A(2^k*x) - 1]^k/k ).

%C Conjectured to consist entirely of integers.

%e G.f.: A(x) = 1 + x + 2*x^2 + 18*x^3 + 476*x^4 + 38358*x^5 +...

%e ...

%e A(x) = 1 + x*exp( [A(2x)-1] + [A(4x)-1]^2/2 + [A(8x)-1]^3/3 +... ).

%o (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,2^k*x+x*O(x^n))-1)^k/k))); polcoeff(A,n)}

%Y Cf. A156908.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Mar 04 2009

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Last modified June 28 19:10 EDT 2022. Contains 354907 sequences. (Running on oeis4.)