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A120056
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G.f.: A(x) satisfies: A(x*A(x)) = A(x)^2/(1+x).
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1
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1, 1, 1, 3, 14, 91, 737, 7096, 78766, 987842, 13797282, 212285511, 3567147508, 65001800879, 1276876433466, 26901212485406, 605144725934525, 14477882030623891, 367106501841287465, 9834718739970491625
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OFFSET
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0,4
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LINKS
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Table of n, a(n) for n=0..19.
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EXAMPLE
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A(x) = 1 + x + x^2 + 3*x^3 + 14*x^4 + 91*x^5 + 737*x^6 +...
A(x)^2 = 1 + 2*x + 3*x^2 + 8*x^3 + 35*x^4 + 216*x^5 + 1693*x^6 +...
A(x*A(x)) = 1 + x + 2*x^2 + 6*x^3 + 29*x^4 + 187*x^5 + 1506*x^6 +...
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PROG
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(PARI) {a(n)=local(A); if(n<1, n==0, A=1+x; for(i=1, n, A=subst(A, x, x*A+x*O(x^n))*(1+x)/A); polcoeff(A, n))}
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CROSSREFS
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Cf. A088792.
Sequence in context: A202294 A029767 A215475 * A125788 A183611 A101220
Adjacent sequences: A120053 A120054 A120055 * A120057 A120058 A120059
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna, Jun 05 2006
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STATUS
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approved
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