A361588 Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled nodes with k strongly connected components and without isolated nodes.

1, 0, 0, 0, 1, 1, 0, 5, 4, 4, 0, 83, 57, 37, 25, 0, 5048, 2411, 1110, 550, 271, 0, 1047008, 325015, 101467, 37140, 15024, 5682, 0, 705422362, 136887749, 27765860, 7139149, 2259378, 780314, 237684, 0, 1580348371788, 183852357683, 23088181536, 3923330808, 907186816, 258971872, 78716548, 20042357

Offset

0,8

Links

Table of n, a(n) for n=0..44.

Formula

T(n,k) = A361582(n,k) - A361582(n-1,k-1).

Example

Triangle begins:
  1;
  0,       0;
  0,       1,      1;
  0,       5,      4,      4;
  0,      83,     57,     37,    25;
  0,    5048,   2411,   1110,   550,   271;
  0, 1047008, 325015, 101467, 37140, 15024, 5682;
  ...

Prog

(PARI) \\ See PARI link in A350794 for program code.
{ my(A=A361588triang(6)); for(n=1, #A, print(A[n])) }

Crossrefs

Column k=1 is A035512.

Main diagonal is A361589.

Row sums are A053598.

Cf. A350794, A361582, A361587, A361590.

Sequence in context: A019179 A206568 A361587 * A304656 A354209 A220248

Adjacent sequences: A361585 A361586 A361587 * A361589 A361590 A361591

Keyword

nonn,tabl

Author

Andrew Howroyd, Mar 16 2023

Status

approved