A350783 Triangle read by rows: T(n,k) is the number of n-element unlabeled N-free posets with k connected components.

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

Author

Salah Uddin Mohammad, Jan 16 2022

Keywords

• nonn
• tabl

Examples

			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;
  ...
		

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.

Crossrefs

Row sums give A202182.

Column 1 is A202180.

Cf. A263864 (all posets), A349488 (disconnected).