The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A093352 Number of labeled n-vertex graphs without a 2-component. 5
 1, 1, 1, 5, 55, 959, 31883, 2076383, 267530657, 68644357201, 35172312944057, 36025019516955853, 73784654524456043287, 302228644804839247744495, 2475873364061564307502565395, 40564787473148108729970731074007, 1329227698679709317077126629247388161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..50 FORMULA E.g.f.: exp(-x^2/2)*Sum_{n>=0} 2^binomial(n,2)*x^n/n!. a(n) = n!*Sum_{q=0..floor(n/2)} ((-1)^q/(2^q*q!))*(2^C(n-2*q,2)/(n-2*q)!). - Marko Riedel, Apr 05 2022 MAPLE A093352 := n -> n!*add((-1)^q/2^q/q!*2^binomial(n-2*q, 2)/(n-2*q)!, q=0..floor(n/2)); # Marko Riedel, Apr 05 2022 MATHEMATICA nn = 15; g = Sum[2^Binomial[n, 2] x^n/n!, {n, 0, nn}]; Range[0, nn]! CoefficientList[Series[g/Exp[x^2/2], {x, 0, nn}], x] (* Geoffrey Critzer, Aug 27 2013 *) CROSSREFS Cf. A093351, A006129. Sequence in context: A057130 A141357 A357394 * A293013 A195513 A172493 Adjacent sequences: A093349 A093350 A093351 * A093353 A093354 A093355 KEYWORD nonn AUTHOR Goran Kilibarda, Vladeta Jovovic, Apr 26 2004 STATUS approved

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

Last modified June 18 04:26 EDT 2024. Contains 373468 sequences. (Running on oeis4.)