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Search: id:A120667
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| A120667 |
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Number of n-node labeled bipartite graphs without isolated nodes. |
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+0
1
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| 1, 0, 1, 3, 22, 225, 3421, 73668, 2222977, 93033615, 5393456986, 433396737873, 48429436851577, 7548123580987080, 1646092439020192801, 503469306031901522043, 216430661498688457821022
(list; graph; listen)
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OFFSET
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0,4
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FORMULA
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E.g.f.: sqrt( e.g.f. for A052332 ) = sqrt(Sum_{n>=0} exp(x*(2^n-2))*x^n/n!).
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MAPLE
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a:= k-> coeff (series (sqrt (sum (exp (x*(2^n-2)) *x^n/n!, n=0..k)), x, k+1), x, k)*k!: seq (a(k), k=0..20); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 12 2008]
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CROSSREFS
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Cf. A047864.
Sequence in context: A079489 A141152 A073530 this_sequence A161567 A141006 A042703
Adjacent sequences: A120664 A120665 A120666 this_sequence A120668 A120669 A120670
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Jun 23 2007
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EXTENSIONS
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More terms from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 12 2008
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