A361582 Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled nodes with k strongly connected components.

1, 0, 1, 0, 1, 2, 0, 5, 5, 6, 0, 83, 62, 42, 31, 0, 5048, 2494, 1172, 592, 302, 0, 1047008, 330063, 103961, 38312, 15616, 5984, 0, 705422362, 137934757, 28095923, 7243110, 2297690, 795930, 243668, 0, 1580348371788, 184557780045, 23226116293, 3951426731, 914429926, 261269562, 79512478, 20286025

Offset: 0

Author

Andrew Howroyd, Mar 16 2023

Keywords

• nonn
• tabl

Examples

			Triangle begins:
  1;
  0,       1;
  0,       1,      2;
  0,       5,      5,      6;
  0,      83,     62,     42,    31;
  0,    5048,   2494,   1172,   592,   302;
  0, 1047008, 330063, 103961, 38312, 15616, 5984;
  ...
		

Links

• Wikipedia, Strongly connected component.

Crossrefs

Column k=1 is A035512.

Main diagonal is A003087.

Row sums are A000273.

The labeled version is A361455.

Cf. A106238, A350794, A361587, A361588.

Programs

PARI

\\ See PARI link in A350794 for program code.
{ my(A=A361582triang(6)); for(n=1, #A, print(A[n])) }