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A126729
Number of graphs on n nodes with edge chromatic number 3.
0
0, 0, 1, 5, 14, 46, 123, 375, 1061, 3331
OFFSET
1,4
CROSSREFS
A diagonal of triangle in A123962.
Sequence in context: A270636 A077335 A176640 * A336006 A098730 A244236
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 16 2007
STATUS
approved