cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A263284 Triangle read by rows: T(n,k) is the number of unlabeled simple graphs on n vertices with domination number k.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 4, 5, 1, 1, 11, 16, 5, 1, 1, 34, 94, 21, 5, 1, 1, 156, 708, 152, 21, 5, 1, 1, 1044, 9384, 1724, 166, 21, 5, 1, 1, 12346, 221135, 38996, 1997, 166, 21, 5, 1, 1, 274668, 9877969, 1800340, 49961, 2036, 166, 21, 5, 1, 1
Offset: 1

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Author

Christian Stump, Oct 13 2015

Keywords

Comments

The domination number of a graph is given by the minimum size of a dominating set of vertices. A dominating set of vertices is a subset of the vertex set of such that every vertex is either in this subset or adjacent to an element of this subset.
For any graph the domination number is greater than or equal to the irredundance number (A332404) and less than or equal to the independent domination number (A332402). - Andrew Howroyd, Feb 13 2020

Examples

			Triangle begins:
       1;
       1,       1;
       2,       1,       1;
       4,       5,       1,     1;
      11,      16,       5,     1,    1;
      34,      94,      21,     5,    1,   1;
     156,     708,     152,    21,    5,   1,  1;
    1044,    9384,    1724,   166,   21,   5,  1, 1;
   12346,  221135,   38996,  1997,  166,  21,  5, 1, 1;
  274668, 9877969, 1800340, 49961, 2036, 166, 21, 5, 1, 1;
  ...
		

Crossrefs

Row sums are A000088.
Columns k=1..2 are A000088(n-1), A332625.

Formula

T(n,k) = T(n-1,k-1) for 2*(k-1) >= n. - Andrew Howroyd, Feb 17 2020

Extensions

Extended to 10 rows by Eric W. Weisstein, May 18 2017

A286958 Triangle read by rows: T(n,k) is the number of graphs with n vertices with connected domination number k.

Original entry on oeis.org

1, 1, 2, 4, 2, 11, 8, 2, 34, 62, 14, 2, 156, 514, 163, 18, 2, 1044, 7147, 2583, 317, 24, 2, 12346, 170803, 70667, 6720, 513, 29, 2, 274668, 7613603, 3566498, 247454, 13525, 785, 36, 2
Offset: 1

Views

Author

Eric W. Weisstein, May 17 2017

Keywords

Examples

			Triangle begins:
    1;
    1;
    2;
    4,   2;
   11,   8,   2;
   34,  62,  14,  2;
  156, 514, 163, 18, 2;
  ...
		

Crossrefs

Row sums are A001349.
Column k=1 is A000088(n-1).

A332406 Number of simple graphs on n unlabeled nodes with total domination number 2.

Original entry on oeis.org

0, 1, 2, 6, 19, 96, 670, 8191, 183149, 7888271
Offset: 1

Views

Author

Andrew Howroyd, Feb 13 2020

Keywords

Crossrefs

Column k=2 of A332400.
Showing 1-3 of 3 results.