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Number of diameter-2-critical graphs with n nodes.
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%I #22 Jun 02 2022 10:09:38

%S 1,2,3,5,10,30,103,519

%N Number of diameter-2-critical graphs with n nodes.

%C The first 10 terms were obtained by filtering the list of non-isomorphic connected graphs, see McKay et al., 2013.

%H J. A. MacDougall and R. B. Eggleton, <a href="https://www.researchgate.net/publication/263930066_Triangle-free_and_Triangle-saturated_Graphs">Triangle-free and triangle-saturated Graphs</a>, Journal of Combinatorial Mathematics and Combinatorial Computing, 25:3-21, 1997.

%H B. D. McKay and A. Piperno, <a href="http://dx.doi.org/10.1016/j.jsc.2013.09.003">Practical Graph Isomorphism, II</a>, J. Symbolic Computation 60 (2013), 94-112.

%e The diameter-2-critical graphs for n=3,4,5 are K_{1,2}; K_{1,3}, C_4; K_{1,4}, K_{2,3}, C_5.

%K nonn,more

%O 3,2

%A _Miodrag Zivkovic_, Dec 17 2019