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 1-10 of 11 results. Next

A352216 Largest number of maximal diamond-free node-induced subgraphs of an n-node graph.

Original entry on oeis.org

1, 1, 1, 4, 7, 11, 21, 36, 62
Offset: 1

Views

Author

Pontus von Brömssen, Mar 08 2022

Keywords

Comments

This sequence is log-superadditive, i.e., a(m+n) >= a(m)*a(n). By Fekete's subadditive lemma, it follows that the limit of a(n)^(1/n) exists and equals the supremum of a(n)^(1/n).
a(10) >= 102, because the complement of 2*C_5 has 102 maximal diamond-free subgraphs. It is likely that this is optimal.

Examples

			All graphs with at most three nodes are diamond-free, so a(n) = 1 for n <= 3 and any graph is optimal.
For 4 <= n <= 9, the following are all optimal graphs, i.e., graphs that have n nodes and a(n) maximal diamond-free subgraphs:
  n = 4: the diamond graph;
  n = 5: the wheel graph;
  n = 6: the complement of the H graph, the complement of P_3 + P_3 (the disjoint union of two paths of length 2), and the octahedral graph;
  n = 7: the complement of P_3 + P_4;
  n = 8: the complement of P_3 + C_5, and the complement of 2*P_4;
  n = 9: the complement of P_4 + C_5.
		

Crossrefs

Cf. A242790.
For a list of related sequences, see cross-references in A342211.

Formula

a(m+n) >= a(m)*a(n).
Limit_{n->oo} a(n)^(1/n) >= 102^(1/10) = 1.58803... .

A243250 Number of unlabeled, connected graphs on n vertices with at least one subgraph isomorphic to a diamond graph.

Original entry on oeis.org

0, 0, 0, 2, 10, 73, 688, 10150, 253396, 11629559
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 01 2014

Keywords

Formula

a(n) = A001349(n) - A242790(n).

A243560 Number of simple connected graphs with n nodes that are Hamiltonian and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

1, 0, 1, 1, 2, 9, 27, 190, 1750, 25658, 531204
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A003216 (Hamiltonian graphs).

Extensions

a(11) added using tinygraph by Falk Hüffner, Aug 15 2017

A243561 Number of simple connected graphs with n nodes that are distance regular and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 3, 2, 4
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A241814 (distance regular graphs).

A243562 Number of simple connected graphs with n nodes that are Eulerian and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

1, 0, 1, 1, 2, 3, 8, 21, 79, 334, 2190
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A003049 (Eulerian graphs).

Extensions

a(11) from Max Alekseyev, Sep 12 2023

A243563 Number of simple connected graphs with n nodes that are non-integral and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

0, 0, 1, 3, 10, 35, 162, 964, 7682, 86994
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond-free graphs), A241842 (non-integral graphs).

A243564 Number of simple connected graphs with n nodes that are integral and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

1, 1, 1, 1, 1, 4, 3, 3, 2, 18
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A064731 (integral graphs).

A243565 Number of simple connected graphs with n nodes that are planar and have no subgraph isomorphic to diamond graph.

Original entry on oeis.org

1, 1, 2, 4, 11, 38, 159, 882, 6242, 55316, 578130, 6774786
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A003094 (planar graphs).

Extensions

a(11)-a(12) added using tinygraph by Falk Hüffner, May 09 2019

A243567 Number of simple connected graphs with n nodes that are have no subgraph isomorphic to diamond graph or the bowtie graph.

Original entry on oeis.org

1, 1, 2, 4, 10, 36, 141, 784, 5626, 56249, 774266, 14750595
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (diamond free graphs), A242792 (bowtie free graphs).

Extensions

a(11)-a(12) added using tinygraph by Falk Hüffner, Sep 23 2020

A243568 Number of simple connected graphs with n nodes that are have no subgraph isomorphic to diamond graph or the bull graph.

Original entry on oeis.org

1, 1, 2, 4, 9, 26, 80, 340, 1690, 11432, 101142, 1228608, 20329150
Offset: 1

Views

Author

Travis Hoppe and Anna Petrone, Jun 06 2014

Keywords

Crossrefs

Cf. A242790 (no diamond subgraphs), A244427 (no bull subgraphs).

Extensions

a(11)-a(13) added using tinygraph by Falk Hüffner, Sep 23 2020
Showing 1-10 of 11 results. Next