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Search: id:A112805
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| A112805 |
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Expansion of solution of functional equation. |
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+0
1
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| 1, 1, 1, 1, 1, 2, 5, 11, 21, 37, 66, 127, 261, 545, 1119, 2255, 4529, 9202, 18989, 39566, 82614, 172272, 359159, 750699, 1575649, 3319942, 7012833, 14834345, 31414423, 66619692, 141526459, 301202699, 642055773, 1370429491, 2928418794
(list; graph; listen)
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OFFSET
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1,6
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FORMULA
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G.f. A(x)=y satisfies y=x+(xy)/(1-(xy)^2).
Series reversion of g.f. A(x) is -A(-x).
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PROGRAM
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(PARI) {a(n)=local(A); if(n<1, 0, A=x+O(x^2); for(k=1, n, A=x+subst(x/(1-x^2), x, x*A)); polcoeff(A, n))}
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CROSSREFS
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Sequence in context: A137356 A103198 A003522 this_sequence A119970 A082775 A023548
Adjacent sequences: A112802 A112803 A112804 this_sequence A112806 A112807 A112808
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Sep 20 2005
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