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Search: id:A118410
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| A118410 |
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G.f. A(x) = Sum_{n>=0} a(n)*x^n/2^(n*(n-1)/2) satisfies: A(x) = Sum_{n>=0} A(x)^n*x^n/2^(n*(n-1)/2). |
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+0
2
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| 1, 1, 3, 21, 321, 10385, 699073, 96908737, 27478721537, 15863659383041, 18583701166494721, 44066148876930001921, 211105432749968736673793, 2040201553888722742048509953, 39729701298130761785818052935681
(list; graph; listen)
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OFFSET
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0,3
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FORMULA
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G.f.: A(x) = (1/x)*series_reversion[x/Sum_{n>=0} x^n/2^(n*(n-1)/2)].
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EXAMPLE
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A(x) = 1 + x + 3*x^2/2 + 21*x^3/8 + 321*x^4/64 + 10385*x^5/1024 +...
A(x) = 1 + x*A(x) + x^2*A(x)^2/2 + x^3*A(x)^3/8 +...
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PROGRAM
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(PARI) {a(n)=2^(n*(n-1)/2)*polcoeff(1/x*serreverse(x/sum(k=0, n, x^k/2^(k*(k-1)/2)+x*O(x^n))), n)}
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CROSSREFS
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Cf. A117401.
Sequence in context: A055555 A005329 A134528 this_sequence A125054 A113085 A083228
Adjacent sequences: A118407 A118408 A118409 this_sequence A118411 A118412 A118413
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Apr 27 2006
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