A263863 Triangle read by rows: T(n,k) (n>=0, k>=n+1) is the number of posets with n elements and k chains.

1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 3, 3, 2, 2, 0, 3, 0, 0, 0, 1, 1, 1, 3, 5, 8, 5, 7, 4, 8, 2, 5, 1, 5, 0, 3, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1

Offset

0,7

Comments

Row sums give A000112.

Links

Table of n, a(n) for n=0..47.

FindStat - Combinatorial Statistic Finder, The number of chains of a poset.

Example

Triangle begins:
1,
1,
1,1,
1,1,2,0,1,
1,1,3,3,2,2,0,3,0,0,0,1,
1,1,3,5,8,5,7,4,8,2,5,1,5,0,3,0,0,0,4,0,0,0,0,0,0,0,1,
...

Crossrefs

Cf. A000112.

Sequence in context: A254045 A024996 A187596 * A134655 A262124 A199954

Adjacent sequences: A263860 A263861 A263862 * A263864 A263865 A263866

Keyword

nonn,tabf

Author

Christian Stump, Oct 28 2015

Status

approved