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A263864 Triangle read by rows: T(n,k) (n>=1, k>=1) is the number of posets with n elements whose Hasse diagram has k connected components. 7
1, 1, 1, 3, 1, 1, 10, 4, 1, 1, 44, 13, 4, 1, 1, 238, 60, 14, 4, 1, 1, 1650, 312, 63, 14, 4, 1, 1, 14512, 2075, 328, 64, 14, 4, 1, 1, 163341, 17316, 2159, 331, 64, 14, 4, 1, 1, 2360719, 186173, 17801, 2175, 332, 64, 14, 4, 1, 1, 43944974, 2594568, 189406, 17885, 2178, 332, 64, 14, 4, 1, 1, 1055019099, 47041877 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
Multiset transformation of A000608.
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.
Wikipedia, Hasse diagram
EXAMPLE
Triangle begins:
1;
1, 1;
3, 1, 1;
10, 4, 1, 1;
44, 13, 4, 1, 1;
...
CROSSREFS
Cf. A000112 (row sums), A000608 (k=1).
Sequence in context: A268115 A106268 A267655 * A060543 A267751 A185996
KEYWORD
nonn,tabl
AUTHOR
Christian Stump, Oct 28 2015
EXTENSIONS
More terms from R. J. Mathar, Jul 12 2020
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)