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A218378 Number of simple labeled graphs on n nodes with all odd size components. 1
1, 1, 1, 5, 17, 769, 4609, 1882805, 15138593, 66365067361, 664157177281, 35645315131333445, 427773958289546417, 301274983519644591252769, 4217875813061550908307649, 40527712572140444650575170520245, 648443738687003872454538321727553 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Table of n, a(n) for n=0..16.

FORMULA

E.g.f.: exp( (A(x) - A(-x))/2 ) where A(x) is the e.g.f. for A001187.

MATHEMATICA

nn=21; a=Sum[2^Binomial[n, 2]x^n/n!, {n, 0, nn}]; c=Range[0, nn]! CoefficientList[Series[ Log[a]+1, {x, 0, nn}], x]; cox= Sum[c[[i]]x^(i-1)/(i-1)!, {i, 2, nn, 2}]; Select[Range[0, nn]! CoefficientList[Series[Exp[cox], {x, 0, nn}], x], #>0&]

CROSSREFS

Cf. A218377, A182124.

Sequence in context: A070294 A161469 A245568 * A119531 A248921 A172996

Adjacent sequences:  A218375 A218376 A218377 * A218379 A218380 A218381

KEYWORD

nonn

AUTHOR

Geoffrey Critzer, Oct 27 2012

STATUS

approved

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Last modified October 21 10:57 EDT 2018. Contains 316414 sequences. (Running on oeis4.)