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A317634
Number of caps (also clutter partitions) of clutters (connected antichains) spanning n vertices.
11
1, 0, 1, 9, 315, 64880
OFFSET
0,4
COMMENTS
A kernel of a clutter is the restriction of the edge set to all edges contained within some connected vertex set. A clutter partition is a set partition of the edge set using kernels.
EXAMPLE
The a(3) = 9 clutter partitions:
{{{1,2,3}}}
{{{1,3},{2,3}}}
{{{1,2},{2,3}}}
{{{1,2},{1,3}}}
{{{1,3}},{{2,3}}}
{{{1,2}},{{2,3}}}
{{{1,2}},{{1,3}}}
{{{1,2},{1,3},{2,3}}}
{{{1,2}},{{1,3}},{{2,3}}}
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Aug 02 2018
STATUS
approved