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Search: id:A141149
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| A141149 |
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G.f. satisfies: A(x) = x*(1 + A(A(x)))/(1 - A(A(x))). |
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+0
1
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| 1, 2, 10, 74, 682, 7274, 86386, 1116338, 15464818, 227315378, 3519165370, 57067589306, 965272138714, 16974057490010, 309490272908386, 5838392491816418, 113747315349651298, 2285212240930687202
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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G.f. satisfies: A( x*(1 - A(x))/(1 + A(x)) ) = x.
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EXAMPLE
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A(x) = x + 2*x^2 + 10*x^3 + 74*x^4 + 682*x^5 + 7274*x^6 + 86386*x^7 +...
A(A(x)) = x + 4*x^2 + 28*x^3 + 256*x^4 + 2752*x^5 + 33124*x^6 + 434524*x^7 +...
The series reversion of A(x) equals:
x*(1-A(x))/(1+A(x)) = x - 2*x^2 - 2*x^3 - 14*x^4 - 110*x^5 - 1058*x^6 -...
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PROGRAM
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(PARI) {a(n)=local(A=x+x^2); if(n<1, 0, for(i=1, n, A=serreverse(x*((1-A)/(1+A+x*O(x^n))))); polcoeff(A, n))}
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CROSSREFS
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Adjacent sequences: A141146 A141147 A141148 this_sequence A141150 A141151 A141152
Sequence in context: A088189 A001395 A047853 this_sequence A046863 A000698 A092881
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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 11 2008
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