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A350783
Triangle read by rows: T(n,k) is the number of n-element unlabeled N-free posets with k connected components.
0
1, 1, 1, 3, 1, 1, 9, 4, 1, 1, 31, 12, 4, 1, 1, 115, 46, 13, 4, 1, 1, 474, 173, 49, 13, 4, 1, 1, 2097, 727, 188, 50, 13, 4, 1, 1, 9967, 3195, 795, 191, 50, 13, 4, 1, 1, 50315, 15017, 3502, 810, 192, 50, 13, 4, 1, 1
OFFSET
1,4
LINKS
Salah Uddin Mohammad, Md. Shah Noor, and Md. Rashed Talukder, An Exact Enumeration of the Unlabeled Disconnected Posets, J. Int. Seq., Vol. 25 (2022), Article 22.5.4.
EXAMPLE
Triangle begins:
1;
1, 1;
3, 1, 1;
9, 4, 1, 1;
31, 12, 4, 1, 1;
115, 46, 13, 4, 1, 1;
474, 173, 49, 13, 4, 1, 1;
2097, 727, 188, 50, 13, 4, 1, 1;
9967, 3195, 795, 191, 50, 13, 4, 1, 1;
50315, 15017, 3502, 810, 192, 50, 13, 4, 1, 1;
...
CROSSREFS
Row sums give A202182.
Column 1 is A202180.
Cf. A263864 (all posets), A349488 (disconnected).
Sequence in context: A069605 A080510 A350772 * A124496 A074881 A142992
KEYWORD
nonn,tabl
AUTHOR
STATUS
approved