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A238427
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Expansion of F(x) where F(x) = 1 + x / (1 - x * F(x) * F(+x^2) ).
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1
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1, 1, 1, 2, 5, 12, 31, 81, 219, 599, 1669, 4698, 13378, 38414, 111200, 324026, 949930, 2799477, 8289481, 24649698, 73580353, 220402603, 662285725, 1995853152, 6030654313, 18266757996, 55454844238, 168704450182, 514231352572, 1570282693387, 4803220361258, 14715518413613, 45150691283345, 138726758012623
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OFFSET
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0,4
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COMMENTS
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What does this sequence count?
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LINKS
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PROG
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(PARI)
N=66; R=O('x^N); x='x+R;
F = 1; for (k=1, N+1, F = 1 + x / (1 - x * F * subst(F, 'x, 'x^2) ) + R; );
Vec(F)
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CROSSREFS
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Cf. A238426: F(x) = 1 + x / (1 - x * F(x) * F(-x^2) ).
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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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