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Search: id:A156171
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| A156171 |
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G.f.: A(x) = exp( Sum_{n>=1} [x/(1 - 2^n*x)]^n/n ), a power series in x with integer coefficients. |
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+0
2
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| 1, 1, 3, 11, 53, 357, 3521, 51665, 1122135, 35638903, 1639453459, 108526044099, 10298220348807, 1396920580458279, 270394562069007327, 74574294532698008703, 29276455806256470979269
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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G.f.: A(x) = 1 + x + 3*x^2 + 11*x^3 + 53*x^4 + 357*x^5 + 3521*x^6 +...
log(A(x)) = x + 5*x^2/2 + 25*x^3/3 + 161*x^4/4 + 1441*x^5/5 + 18305*x^6/6 +...
Log series:
log(A(x)) = Sum_{n>=1} (x + 2^n*x^2 + 4^n*x^3 +...+ 2^(n(k-1))*x^k +...)^n/n.
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PROGRAM
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(PARI) {a(n)=polcoeff(exp(sum(m=1, n, x^m/(1-2^m*x+x*O(x^n))^m/m)), n)}
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CROSSREFS
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Cf. A156170, A155200, A156100.
Sequence in context: A000255 A121580 A081367 this_sequence A129093 A057325 A054700
Adjacent sequences: A156168 A156169 A156170 this_sequence A156172 A156173 A156174
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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), Feb 05 2009
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