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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
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
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.)