A350910 -id:A350910 - cp's OEIS frontend

A219889 Number of directed 2-regular graphs on n nodes.

1, 2, 5, 23, 92, 624, 5021, 47034, 494320, 5719769, 71971687

Offset: 3

N. J. A. Sloane, Nov 30 2012

Gunnar Brinkmann, Generating regular directed graphs, Discrete Math., 313 (2012), 1-7.
R. J. Mathar, OEIS A219889
Richard J. Mathar, 2-regular Digraphs of the Lovelock Lagrangian, arXiv:1903.12477 [math.GM], 2019.

Column k=2 of A350910.

Cf. A096368, A219890, A219891, A219892, A219893, A307155 (connected, inverse Euler Trans.), A007107 (labeled), A306827 (multiedges, connected), A002865 (directed 1-regular unlabeled no loops), A005641 (loops allowed)

A219890 Number of directed 3-regular graphs on n nodes.

Original entry on oeis.org

1, 2, 23, 415, 19041, 1104045, 79818336, 6958257941, 720814138673, 87579097910309

Offset: 4

N. J. A. Sloane, Nov 30 2012

Gunnar Brinkmann, Generating regular directed graphs, Discrete Math., 313 (2012), 1-7.

Column k=3 of A350910.

Cf. A096368, A219889, A219890, A219891, A219892, A219893.

A219891 Number of directed 4-regular graphs on n nodes.

Original entry on oeis.org

1, 4, 92, 19041, 6510087, 2983458766, 1775668832509, 1349509467853512

Offset: 5

N. J. A. Sloane, Nov 30 2012

Gunnar Brinkmann, Generating regular directed graphs, Discrete Math., 313 (2012), 1-7.

Column k=4 of A350910.

Cf. A096368, A219889, A219890, A219892, A219893.

A219892 Number of directed 5-regular graphs on n nodes.

Original entry on oeis.org

1, 4, 624, 1104045, 2983458766, 10922621656743

Offset: 6

N. J. A. Sloane, Nov 30 2012

Gunnar Brinkmann, Generating regular directed graphs, Discrete Math., 313 (2012), 1-7.

Column k=5 of A350910.

Cf. A096368, A219889, A219890, A219891, A219893.

A219893 Number of directed 6-regular graphs on n nodes.

Original entry on oeis.org

1, 7, 5021, 79818336, 1775668832509

Offset: 7

N. J. A. Sloane, Nov 30 2012

Gunnar Brinkmann, Generating regular directed graphs, Discrete Math., 313 (2012), 1-7.

Column k=6 of A350910.

Cf. A096368, A219889, A219890, A219891, A219892.

A350912 Triangle read by rows: T(n,k) is the number of oriented graphs on n unlabeled nodes whose underlying graph is k-regular, k = 0..n-1.

Original entry on oeis.org

1, 1, 1, 1, 0, 2, 1, 1, 4, 4, 1, 0, 4, 0, 12, 1, 1, 12, 62, 112, 56, 1, 0, 18, 0, 1602, 0, 456, 1, 1, 40, 2062, 32263, 92980, 46791, 6880, 1, 0, 68, 0, 748576, 0, 11210264, 0, 191536, 1, 1, 140, 103827, 19349672, 616991524, 3319462470, 2729098064, 292115960, 9733056

Offset: 1

Andrew Howroyd, Jan 29 2022

The sum of the in-degree and out-degree at each node is k.

a(2*n,2*n-2) is the number of orientations (up to isomorphism) of the n-cocktail party graph. - Pontus von Brömssen, Apr 03 2022

			Triangle begins:
  1;
  1, 1;
  1, 0,  2;
  1, 1,  4,  4;
  1, 0,  4,  0,   12;
  1, 1, 12, 62,  112, 56;
  1, 0, 18,  0, 1602,  0, 456;
  ...

Andrew Howroyd, Table of n, a(n) for n = 1..253 (rows 1..22)

Row sums are A350913.
Main diagonal is A000568.
The labeled version is A351263.
Cf. A051031 (graphs), A350910 (digraphs).

A350911 Number of regular digraphs on n unlabeled nodes.

Original entry on oeis.org

1, 1, 2, 3, 6, 11, 56, 609, 39346, 8728237, 6126648298, 14487876826313

Offset: 0

Andrew Howroyd, Jan 29 2022

Row sums of A350910.

Cf. A000273, A005176, A329234, A350913.

cp's OEIS Frontend

A219889 Number of directed 2-regular graphs on n nodes.

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A219890 Number of directed 3-regular graphs on n nodes.

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A219891 Number of directed 4-regular graphs on n nodes.

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A219892 Number of directed 5-regular graphs on n nodes.

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A219893 Number of directed 6-regular graphs on n nodes.

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A350912 Triangle read by rows: T(n,k) is the number of oriented graphs on n unlabeled nodes whose underlying graph is k-regular, k = 0..n-1.

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A350911 Number of regular digraphs on n unlabeled nodes.

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