This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A058380 Essentially series series-parallel networks with n labeled edges, multiple edges not allowed. 5
 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 REFERENCES J. W. Moon, Some enumerative results on series-parallel networks, Annals Discrete Math., 33 (1987), 199-226 (the sequence R_n). LINKS S. R. Finch, Series-parallel networks S. R. Finch, Series-parallel networks, July 7, 2003. [Cached copy, with permission of the author] 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 19 03:15 EDT 2019. Contains 328211 sequences. (Running on oeis4.)