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A004108 Number of n-node unlabeled connected graphs without endpoints.
(Formerly M2910)
1, 0, 1, 3, 11, 61, 507, 7442, 197772, 9808209, 902884343, 153723152913, 48443147912137, 28363697921914475, 30996525982586676021, 63502034385272108655525, 244852545421597419740767106, 1783161611489937453151313949442 (list; graph; refs; listen; history; text; internal format)



Also number of n-node unlabeled connected mating graphs, cf. A006024 and A092430 (conjectured by Vladeta Jovovic, proved by G. Kilibarda). - Vladeta Jovovic, Oct 07 2004


F. Harary and E. Palmer, Graphical Enumeration, (1973), formula (8.7.11).

Goran Kilibarda, "Enumeration of unlabeled mating graphs", Belgrade, 2004, to be published.

R. W. Robinson, personal communication.

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1977.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


R. W. Robinson, Table of n, a(n) for n = 1..26

David Cook II, Nested colourings of graphs, arXiv preprint arXiv:1306.0140, 2013

Goran Kilibarda, Enumeration of Unlabeled Mating Graphs, Graphs and Combinatorics, Volume 23, Number 2 / April, 2007, pp. 183-199.

R. W. Robinson, Connected graphs without endpoints - computer printout

Eric Weisstein's World of Mathematics, Connected Graph.


Cf. A059166 (n-node connected labeled graphs without endpoints), A059167 (n-node labeled graphs without endpoints), A004110 (Euler Transform, n-node unlabeled graphs without endpoints).

Cf. A092430 (n-node labeled connected mating graphs).

See also A261919.

Sequence in context: A185385 A024528 A273468 * A203007 A296321 A203768

Adjacent sequences:  A004105 A004106 A004107 * A004109 A004110 A004111




N. J. A. Sloane



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Last modified March 17 14:48 EDT 2018. Contains 300565 sequences. (Running on oeis4.)