A350751 -id:A350751 - cp's OEIS frontend

A350489 Number of strongly connected oriented graphs on n unlabeled nodes.

1, 1, 0, 1, 4, 76, 4232, 611528, 222688092, 205040866270, 484396550160186, 2987729989350536868, 48933147333828638153224, 2160018687398735805070288200, 260218032038985813416099131315377, 86440094822917159858790627703492969772

Offset: 0

Andrew Howroyd, Jan 01 2022

nonn

Andrew Howroyd, Table of n, a(n) for n = 0..50
Andrew Howroyd, PARI Program, Jan 2022.
R. W. Robinson, Counting digraphs with restrictions on the strong components, Combinatorics and Graph Theory '95 (T.-H. Ku, ed.), World Scientific, Singapore (1995), 343-354.
Wikipedia, Strongly connected component

Row sums of A350750.
The labeled version is A350730.
Cf. A001174, A035512, A086345, A350751.

A350489seq(15) \\ See Links for program code.

A350752 Number of unlabeled strongly connected digraphs with n arcs.

Original entry on oeis.org

1, 0, 1, 1, 3, 6, 25, 91, 442, 2241, 12591, 75180, 478648, 3211245, 22635956, 166828221, 1281518573, 10229858290, 84652925554, 724601312400, 6403522811765, 58327076550161, 546764617643250, 5267719312771122, 52096218005705959, 528285485054771639

Offset: 0

Andrew Howroyd, Jan 13 2022

nonn

Row sums of A350753.
Column sums of A057276.
Cf. A035512, A350489, A350751.

A350752seq(20) \\ See PARI link in A350489 for program code.

A350750 Triangle read by rows: T(n,k) is the number of strongly connected oriented graphs on n unlabeled nodes with k arcs, n >= 1, k = 0..n*(n-1)/2.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 5, 18, 27, 19, 6, 0, 0, 0, 0, 0, 0, 1, 8, 80, 333, 765, 1122, 1049, 622, 217, 35, 0, 0, 0, 0, 0, 0, 0, 1, 12, 221, 1875, 8971, 28449, 63845, 105556, 130935, 122607, 85926, 43868, 15506, 3403, 353

Offset: 1

Andrew Howroyd, Jan 13 2022

			Triangle begins:
  [1] 1;
  [2] 0, 0;
  [3] 0, 0, 0, 1;
  [4] 0, 0, 0, 0, 1, 2, 1;
  [5] 0, 0, 0, 0, 0, 1, 5, 18, 27,  19,   6;
  [6] 0, 0, 0, 0, 0, 0, 1,  8, 80, 333, 765, 1122, 1049, 622, 217, 35;
  ...

Andrew Howroyd, Table of n, a(n) for n = 1..1350 (rows 1..20)

Row sums are A350489.
Column sums are A350751.
The labeled version is A350731.
Cf. A057276 (digraphs), A350733, A350734.

\\ See PARI link in A350489 for program code.
{ my(A=A350750rows(7)); for(n=1, #A, print(A[n])) }

cp's OEIS Frontend

A350489 Number of strongly connected oriented graphs on n unlabeled nodes.

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PARI

A350752 Number of unlabeled strongly connected digraphs with n arcs.

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PARI

A350750 Triangle read by rows: T(n,k) is the number of strongly connected oriented graphs on n unlabeled nodes with k arcs, n >= 1, k = 0..n*(n-1)/2.

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Author

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Links

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Programs

PARI