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A079146 Number of unlabeled semitransitive orders on n elements: (1+3)-free posets. 1
1, 2, 5, 15, 49, 173, 639 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

CROSSREFS

Cf. A079145 (labeled semitransitive orders).

Sequence in context: A149941 A149942 A149943 * A000734 A148366 A005751

Adjacent sequences:  A079143 A079144 A079145 * A079147 A079148 A079149

KEYWORD

nonn,more

AUTHOR

Detlef Pauly (dettodet(AT)yahoo.de), Dec 27 2002

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.