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A003515
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Number of series-reduced connected labeled graphs with n nodes.
(Formerly M4009)
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6
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0, 1, 1, 0, 5, 51, 3634, 374119, 73161880, 26545249985, 17904840957826, 22602069719494379, 53938857227326533032, 246107945479472758874483, 2170331943503938546383205218, 37340982087637629911717846092591, 1262915556964772342158139988356979872
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OFFSET
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0,5
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COMMENTS
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Jackson and Reilly paper has typographical error in value for a(12). - Sean A. Irvine, Jun 17 2015
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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PROG
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(PARI) \\ See Jackson & Reilly for e.g.f.
seq(n)={my(A=O(x*x^n)); Vec(serlaplace(log((exp(x/2 - x^2/4 + A)/sqrt(1 + x + A))*sum(k=0, n, (2*exp(-x/(1+x) + A))^binomial(k, 2) * (x*exp((x^2 + A)/(2*(1 + x))))^k / k!))), -(n+1))} \\ Andrew Howroyd, Jan 24 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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