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A304985
Number of labeled clutters (connected antichains) spanning n vertices with singleton edges allowed.
10
1, 1, 4, 40, 1344, 203136, 495598592, 309065330371840, 14369391920653644779049472
OFFSET
0,3
COMMENTS
Only the non-singleton edges are required to form an antichain.
FORMULA
For n > 1, a(n) = A048143(n) * 2^n.
EXAMPLE
The a(2) = 4 clutters:
{{1,2}}
{{1},{1,2}}
{{2},{1,2}}
{{1},{2},{1,2}}
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 23 2018
STATUS
approved