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A322727
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G.f.: A(x) = Sum_{n>=0} ((1+x)^n - x*A(x))^n / 2^(n+1).
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0
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1, 2, 25, 526, 15554, 590575, 27338911, 1492079652, 93776123520, 6669479907548, 529549414923174, 46432923079132507, 4456442206987048919, 464691980829431905959, 52313905571976063712791, 6323967971227649063422416, 817029035199692037187367976, 112348605647113658601511442450, 16383091093205410144470895801204, 2525293749572595915714422633867944
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f. A(x) satisfies:
(1) A(x) = Sum_{n>=0} ((1+x)^n - x*A(x))^n / 2^(n+1).
(2) A(x) = Sum_{n>=0} (1+x)^(n^2) / (2 + x*A(x))^(n+1).
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EXAMPLE
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G.f.: A(x) = 1 + 2*x + 25*x^2 + 526*x^3 + 15554*x^4 + 590575*x^5 + 27338911*x^6 + 1492079652*x^7 + 93776123520*x^8 + 6669479907548*x^9 + ...
such that
A(x) = 1/2 + ((1+x) - x*A(x))/2^2 + ((1+x)^2 - x*A(x))^2/2^3 + ((1+x)^3 - x*A(x))^3/2^4 + ((1+x)^4 - x*A(x))^4/2^5 + ((1+x)^5 - x*A(x))^5/2^6 + ...
also,
A(x) = 1/(2 + x*A(x)) + (1+x)/(2 + x*A(x))^2 + (1+x)^4/(2 + x*A(x))^3 + (1+x)^9/(2 + x*A(x))^4 + (1+x)^16/(2 + x*A(x))^5 + (1+x)^25/(2 + x*A(x))^6 + ...
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MATHEMATICA
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m = 20; A[_] = 0;
Do[A[x_] = Sum[((1+x)^n - x A[x])^n/2^(n+1), {n, 0, k^2}] + O[x]^k, {k, 1, m}];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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