A193357 Triangle read by rows: T(n,k) (n>=1, 1 <= k <= n) = number of n-element unlabeled rigid interval posets of height k.

1, 0, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 8, 6, 1, 0, 1, 20, 29, 10, 1, 0, 1, 51, 128, 75, 15, 1, 0, 1, 134, 555, 500, 160, 21, 1, 0, 1, 367, 2427, 3190, 1480, 301, 28, 1, 0, 1, 1048, 10864, 20129, 12835, 3661, 518, 36, 1, 0, 1, 3119, 50145, 127912, 108308, 41041, 7980, 834, 45, 1, 0, 1, 9655, 239581, 827053, 907923, 441553, 111671, 15828, 1275, 55, 1

Offset: 1

Author

N. J. A. Sloane, Aug 26 2011

Keywords

• nonn
• tabl

Examples

			Triangle begins
1
0 1
0 1 1
0 1 3 1
0 1 8 6 1
0 1 20 29 10 1
0 1 51 128 75 15 1
0 1 134 555 500 160 21 1
0 1 367 2427 3190 1480 301 28 1
0 1 1048 10864 20129 12835 3661 518 36 1
0 1 3119 50145 127912 108308 41041 7980 834 45 1
0 1 9655 239581 827053 907923 441553 111671 15828 1275 55 1
0 1 31024 1186941 5474614 7654921 4664814 1482110 26944 29175 1870 66 1
...
		

Links

• Soheir Mohamed Khamis, Exact Counting of Unlabeled Rigid Interval Posets Regarding or Disregarding Height, Order 29, pp. 443-461 (2012).

Crossrefs

Row sums = A138265. Cf. A193387.