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 A092430 Number of n-node labeled connected mating graphs, cf. A006024. 11
 1, 1, 25, 438, 18388, 1409674, 206682994, 58152537184, 31715884061624, 33827568738189576, 71066571962396085656, 295645506683051376527648, 2444503529745123474354656720, 40269655263141217619453414445968 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,3 COMMENTS Number of n-node unlabeled connected mating graphs = number of n-node unlabeled connected graphs without endpoints, n>2; cf. A004108. The number of graphs of this type with n>=1 nodes and 1<=k<=n components defines the triangle 0; 1,0; 1,0,0; 25,3,0,0; 438,10,0,0,0; 18388,385,15,0,0,0; 1409674,10073,105,0,0,0,0; 206682994,561267,5530,105,0,0,0,0; 58152537184,53672556,197344,1260,0,0,0,0,0; with row sums A007833. - R. J. Mathar, Apr 29 2019 REFERENCES Goran Kilibarda, "Enumeration of unlabeled mating graphs", Belgrade, 2004, to be published. LINKS Andrew Howroyd, Table of n, a(n) for n = 2..50 Goran Kilibarda, Enumeration of Unlabeled Mating Graphs, Graphs and Combinatorics, Volume 23, Number 2 / April, 2007, pp. 183-199. FORMULA From Vladeta Jovovic, Mar 28 2004: (Start) E.g.f.: log((Sum_{n>=0} 2^binomial(n, 2)*log(1+x)^n/n!)/(1+x)). a(n) = A079306(n) + (-1)^n*(n-1)!. (End) PROG (PARI) a(n)={n!*polcoef(log(sum(i=0, n, 2^binomial(i, 2)*log(1+x + O(x*x^n))^i/i!)/(1+x)), n)} \\ Andrew Howroyd, Sep 09 2018 CROSSREFS Cf. A006024, A079306, A007833, A004108. Cf. A059166. Sequence in context: A180800 A004346 A021324 * A018207 A362428 A264382 Adjacent sequences: A092427 A092428 A092429 * A092431 A092432 A092433 KEYWORD nonn AUTHOR Goran Kilibarda, Vladeta Jovovic, Mar 22 2004 STATUS approved

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Last modified May 30 07:21 EDT 2023. Contains 363045 sequences. (Running on oeis4.)