2,1

The next term is known to be 40, 41, 42 or 43 (Exoo, Radziszowski). I had a note here saying that the range had been narrowed to 40 or 41, but I cannot find the source for that remark, so I am not sure it is correct. - N. J. A. Sloane (njas(AT)research.att.com), Feb 14 2007.

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

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

G. Berman and K. D. Fryer, Introduction to Combinatorics. Academic Press, NY, 1972, p. 175.

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 288.

R. E. Greenwood and A. M. Gleason, Combinatorial relations and chromatic graphs, Canad. J. Math., 7 (1955), 1-7.

J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 840.

J. G. Kalbfleisch, Construction of special edge-chromatic graphs, Canad. Math. Bull., 8 (1965), 575-584.

B. D. McKay, personal communication.

H. J. Ryser, Combinatorial Mathematics. Mathematical Association of America, Carus Mathematical Monograph 14, 1963, p. 42.

Jin Xu and C. K. Wong, Self-complementary graphs and Ramsey numbers I, Discrete Math., 223 (2000), 309-326.

Anonymous, Ramsey's Theory

G. Exoo, Ramsey Numbers

R. Getschmann, Enumeration of Small Ramsey Graphs

I. Leader, Friends and Strangers

Math Reference Project, Ramsey Numbers

Online Dictionary of Combinatorics, Ramsey's Theorem

I. Peterson, Math Trek, Party Games

I. Peterson, Math Trek, Party Games

Stanislaw Radziszowski, Small Ramsey Numbers.

Ricardo, Ramsey Number Page

Eric Weisstein's World of Mathematics, Ramsey Number

Wikipedia, Ramsey's Theorem.

A row of the table in A059442. Cf. A120414.

Sequence in context: A086838 A161669 A128261 this_sequence A027424 A134031 A130473

Adjacent sequences: A000788 A000789 A000790 this_sequence A000792 A000793 A000794

nonn,hard,nice

N. J. A. Sloane (njas(AT)research.att.com).