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Search: id:A158265
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| A158265 |
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G.f.: A(x) = exp( Sum_{n>=1} 2*sigma(n,n+1)*x^n/n ). |
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+0
1
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| 1, 2, 11, 74, 697, 8002, 115158, 1949640, 38662510, 872245634, 22150393253, 623661939852, 19296665400632, 650198159192554, 23700604926216759, 928939297013294294, 38956230043045053042, 1740248411222193973416
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Definition: sigma(n,n+1) = Sum_{d|n} d^(n+1): [1,9,82,1057,15626,...].
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EXAMPLE
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G.f.: A(x) = 1 + 2*x + 11*x^2 + 74*x^3 + 697*x^4 + 8002*x^5 +...
log(A(x)) = 2*x + 18*x^2/2 + 164*x^3/3 + 2114*x^4/4 + 31252*x^5/5 +...
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PROGRAM
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(PARI) a(n)=polcoeff(exp(sum(m=1, n, 2*sigma(m, m+1)*x^m/m)+x*O(x^n)), n)
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CROSSREFS
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Cf. A158095, A023881.
Sequence in context: A074609 A114179 A058789 this_sequence A112894 A049363 A055085
Adjacent sequences: A158262 A158263 A158264 this_sequence A158266 A158267 A158268
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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), Mar 29 2009
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