A058380 - OEIS

A058380

Essentially series series-parallel networks with n labeled edges, multiple edges not allowed.

0, 0, 1, 1, 13, 66, 796, 8338, 122326, 1893748, 34717076, 695343144, 15560613872, 379211091416, 10070672083928, 288420300817184, 8877044175277216, 291944826030636000, 10221726849956763136, 379528960298122277536, 14896869800297864928736

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,5

LINKS

Table of n, a(n) for n=0..20.

Steven R. Finch, Series-parallel networks

Steven R. Finch, Series-parallel networks, July 7, 2003. [Cached copy, with permission of the author]

John W. Moon, Some enumerative results on series-parallel networks, Annals Discrete Math., 33 (1987), 199-226 (the sequence R_n).

Index entries for sequences mentioned in Moon (1987)

FORMULA

E.g.f. satisfies A(x) = A058379(x) - log(1+x).

E.g.f.: -1/2 - log(1+x)/2 - LambertW(-exp(-1/2)*sqrt(1+x)/2). - Vaclav Kotesovec, Mar 11 2014

a(n) ~ n^(n-1) / (2*sqrt(2)*(4-exp(1))^(n-1/2)). - Vaclav Kotesovec, Mar 11 2014

MATHEMATICA

CoefficientList[Series[-1/2 - Log[1+x]/2 - LambertW[-E^(-1/2)*Sqrt[1+x]/2], {x, 0, 15}], x]* Range[0, 15]! (* Vaclav Kotesovec, Mar 11 2014 *)

CROSSREFS

Cf. A058379, A058381.

Sequence in context: A268777 A109727 A041320 * A129746 A067863 A257809

Adjacent sequences: A058377 A058378 A058379 * A058381 A058382 A058383

KEYWORD

nonn,nice,easy

AUTHOR

N. J. A. Sloane, Dec 19 2000

STATUS

approved

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