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A003323 Multicolor Ramsey numbers R(3,3,...,3).
(Formerly M2594)
2
3, 6, 17, 66, 327 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

A073591(n) is an upper bound on a(n).

If the edges of a complete graph with at least as many nodes as a(n) are colored with n colors then there is always a monochromatic triangle.

REFERENCES

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

H. W. Gould, personal communication.

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

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

EXAMPLE

a(2)=6 since in a party with at least 6 people, there are three people mutually acquainted or three people mutually unacquainted.

CROSSREFS

Cf. A045652.

Sequence in context: A143093 A117712 A106158 * A073591 A195995 A078318

Adjacent sequences:  A003320 A003321 A003322 * A003324 A003325 A003326

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

Upper bound and additional comments from D. G. Rogers (drogers(AT)turing.une.edu.au), Aug 27 2006

Better definition from Max Alekseyev, Jan 12 2008

Comment corrected by Brian Kell (bkell(AT)cmu.edu), Feb 14 2010

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Last modified February 15 23:53 EST 2012. Contains 205860 sequences.