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 A093857 Number of unlabeled ordered T_0-multigraphs with n edges. 0
 2, 0, 2, 22, 278, 4436, 88852, 2184456, 64459628, 2239805712, 90214284410, 4157479612606, 216841733604410, 12682329307742732, 825184186612617418, 59320610243634707134, 4683176986971809187614, 403867178883936416642928, 37864927166010206186524472, 3843160755696708555996620560 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Table of n, a(n) for n=0..19. FORMULA E.g.f.: 2*exp((2-x)/(2*x-2))*sum(n>=0, (1-x)^(-binomial(n, 2))/n! ). PROG (PARI) default(realprecision, 110); N=50; x='x+O(x^N); s=2*exp((2-x)/(2*x-2))*sum(n=0, 66, (1-x)^(-binomial(n, 2))/n!); s=serlaplace(s); s=round(s); Vec(s) /* show terms */ /* Joerg Arndt, Apr 28 2012 */ CROSSREFS Sequence in context: A077184 A077183 A101030 * A056949 A346235 A281326 Adjacent sequences: A093854 A093855 A093856 * A093858 A093859 A093860 KEYWORD easy,nonn AUTHOR Goran Kilibarda, Vladeta Jovovic, May 21 2004 EXTENSIONS Terms >=4157479612606 by Joerg Arndt, Apr 28 2012. STATUS approved

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Last modified July 17 05:50 EDT 2024. Contains 374360 sequences. (Running on oeis4.)