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A126741 Number of connected triangle-free graphs on n nodes with chromatic number 4. 1
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 23, 1085, 75127, 6384013 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,12

LINKS

Table of n, a(n) for n=1..15.

Keith M. Briggs, Combinatorial Graph Theory

CROSSREFS

See A116079 for further information.

Sequence in context: A042015 A042012 A128404 * A273477 A202656 A061063

Adjacent sequences:  A126738 A126739 A126740 * A126742 A126743 A126744

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(15) from Michael Sollami, Feb 04 2012.

STATUS

approved

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Last modified June 28 17:16 EDT 2017. Contains 288839 sequences.