A047684 - OEIS

A047684

Number of reduced contexts on n unlabeled objects.

1, 2, 9, 126, 13596, 108096891

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Equivalently, number of closure systems on n points, up to isomorphism.

REFERENCES

Bernhard Ganter, Rudolf Wille: Formal Concept Analysis, Springer-Verlag, 1999, ISBN 3-540-62771-5, p. 59.

LINKS

CROSSREFS

KEYWORD

hard,nonn,nice

AUTHOR

Bernhard Ganter (ganter(AT)math.tu-dresden.de)

EXTENSIONS

a(6) from Klaus Hoffmann, Jan 01 2016

STATUS

approved