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A006870
Number of quasi-orders with n elements.
(Formerly M2755)
4
1, 1, 3, 8, 26, 94, 435, 2564, 19983, 205729
OFFSET
0,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
M. Erné and K. Stege, The number of partially ordered (labeled) sets, Preprint, 1989. (Annotated scanned copy)
M. Erné and K. Stege, Counting Finite Posets and Topologies, Order, 8 (1991), 247-265.
CROSSREFS
Sequence in context: A148822 A124528 A320344 * A348620 A058802 A054097
KEYWORD
nonn,nice,more
STATUS
approved