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A321256
Regular triangle where T(n,k) is the number of non-isomorphic connected set systems of weight n with density -1 <= k <= n-2.
2
1, 1, 0, 2, 0, 0, 4, 0, 0, 0, 6, 1, 0, 0, 0, 13, 5, 0, 0, 0, 0, 23, 12, 2, 0, 0, 0, 0, 49, 36, 11, 0, 0, 0, 0, 0, 100, 95, 39, 5, 0, 0, 0, 0, 0, 220, 262, 143, 32, 1, 0, 0, 0, 0, 0
OFFSET
1,4
COMMENTS
A set system is a finite set of finite nonempty sets. The density of a set system is the sum of sizes of each part (weight) minus the number of parts minus the number of vertices.
EXAMPLE
Triangle begins:
1
1 0
2 0 0
4 0 0 0
6 1 0 0 0
13 5 0 0 0 0
23 12 2 0 0 0 0
49 36 11 0 0 0 0 0
100 95 39 5 0 0 0 0 0
220 262 143 32 1 0 0 0 0 0
CROSSREFS
First column is A321228. Row sums are A007718.
Sequence in context: A216394 A028590 A074644 * A130123 A319935 A136337
KEYWORD
nonn,tabl,more
AUTHOR
Gus Wiseman, Nov 01 2018
STATUS
approved