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A304996 Number of unlabeled antichains of finite sets spanning up to n vertices with singleton edges allowed. 10
1, 2, 6, 24, 166, 3266, 826308 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..6.

EXAMPLE

Non-isomorphic representatives of the a(3) = 24 antichains:

{}

{{1}}

{{1,2}}

{{1,2,3}}

{{1},{2}}

{{2},{1,2}}

{{3},{1,2}}

{{3},{1,2,3}}

{{1,3},{2,3}}

{{1},{2},{3}}

{{1},{2},{1,2}}

{{2},{3},{1,3}}

{{2},{3},{1,2,3}}

{{3},{1,2},{2,3}}

{{3},{1,3},{2,3}}

{{1,2},{1,3},{2,3}}

{{1},{2},{3},{2,3}}

{{1},{2},{3},{1,2,3}}

{{2},{3},{1,2},{1,3}}

{{2},{3},{1,3},{2,3}}

{{3},{1,2},{1,3},{2,3}}

{{1},{2},{3},{1,3},{2,3}}

{{2},{3},{1,2},{1,3},{2,3}}

{{1},{2},{3},{1,2},{1,3},{2,3}}

CROSSREFS

Partial sums of A304997.

Cf. A006126, A261005, A304997, A304998, A304999, A305000, A305001.

Cf. A000372, A014466, A293993, A319639, A319721, A326704, A326972.

Sequence in context: A012361 A308111 A121773 * A012711 A073973 A034874

Adjacent sequences:  A304993 A304994 A304995 * A304997 A304998 A304999

KEYWORD

nonn,more

AUTHOR

Gus Wiseman, May 23 2018

EXTENSIONS

a(5)-a(6) from Andrew Howroyd, Aug 14 2019

STATUS

approved

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Last modified February 24 18:55 EST 2021. Contains 341584 sequences. (Running on oeis4.)