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 A179469 G.f. satisfies: A(x) = exp( Sum_{n>=1} 2^n*A(x^n)*x^n/n ). 0

%I

%S 1,2,8,32,140,624,2928,14048,69200,347040,1768120,9122144,47572128,

%T 250341312,1327718272,7089595552,38082093120,205638343552,

%U 1115635692576,6078058719232,33239328613648,182402290944576,1004073853702320

%N G.f. satisfies: A(x) = exp( Sum_{n>=1} 2^n*A(x^n)*x^n/n ).

%e G.f.: A(x) = 1 + 2*x + 8*x^2 + 32*x^3 + 140*x^4 + 624*x^5 + +...

%e log(A(x)) = 2*A(x) + 4*A(x^2)*x^2/2 + 8*A(x^3)*x^3/3 + 16*A(x^4)*x^4/4 +...

%o (PARI) {a(n)=local(A=1+x);for(i=1,n,A=exp(sum(m=1,n,subst(A,x,x^m+x*O(x^n))*2^m*x^m/m)));polcoeff(A,n)}

%K nonn

%O 0,2

%A _Paul D. Hanna_, Jul 15 2010

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Last modified December 7 22:50 EST 2021. Contains 349590 sequences. (Running on oeis4.)