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Search: id:A141119
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| A141119 |
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G.f. A(x) satisfies: A(A(A(A(x)))) = x + 16*x^2. |
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+0
4
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| 1, 4, -48, 960, -23296, 616448, -16830464, 456228864, -11849367552, 281940983808, -5672090468352, 75759202861056, 445162740252672, -73915606654517248, 2987936359374651392, -82722417189670879232
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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G.f.: A(x) = x + 4*x^2 - 48*x^3 + 960*x^4 - 23296*x^5 + 616448*x^6 -+...
A(A(x)) = x + 8*x^2 - 64*x^3 + 1024*x^4 - 20480*x^5 + 442368*x^6 -+...
A(A(A(x))) = x + 12*x^2 - 48*x^3 + 576*x^4 - 8960*x^5 + 143360*x^6 -+...
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PROGRAM
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(PARI) {a(n, m=4)=local(F=x+m*x^2+x*O(x^n), G); if(n<1, 0, for(k=3, n, G=F+x*O(x^k); for(i=1, m-1, G=subst(F, x, G)); F=F+((-polcoeff(G, k))/m)*x^k); return(polcoeff(F, n, x)))}
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CROSSREFS
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Cf. A027436, A141118, A141120, A141121.
Sequence in context: A089448 A167141 A162676 this_sequence A052714 A144828 A138448
Adjacent sequences: A141116 A141117 A141118 this_sequence A141120 A141121 A141122
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KEYWORD
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sign
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jun 05 2008
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