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Search: id:A141370
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| A141370 |
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G.f. satisfies: A(x) = x + A(A(A(x)^2)). |
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+0
4
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| 1, 1, 2, 7, 26, 104, 436, 1894, 8444, 38418, 177656, 832548, 3945156, 18871524, 91003360, 441927367, 2159282462, 10607708284, 52363342484, 259601860898, 1292041756732, 6453179670344, 32334136480656, 162487089008766
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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G.f. satisfies: A( x - A(A(x^2)) ) = x.
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EXAMPLE
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G.f.: A(x) = x + x^2 + 2*x^3 + 7*x^4 + 26*x^5 + 104*x^6 + 436*x^7 +...
The series reversion of A(x) = x - A(A(x^2)), where
A(A(x^2)) = x^2 + 2*x^4 + 6*x^6 + 25*x^8 + 116*x^10 + 574*x^12 + 2972*x^14 +...
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PROGRAM
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(PARI) {a(n)=local(A=x+x^2); for(i=1, n, A=x+subst(A, x, subst(A, x, A^2+x*O(x^n)))); polcoeff(A, n)}
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CROSSREFS
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Cf. A141371, A141372.
Sequence in context: A150545 A150546 A151296 this_sequence A150547 A150548 A150549
Adjacent sequences: A141367 A141368 A141369 this_sequence A141371 A141372 A141373
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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), Jun 28 2008
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