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.

Previous Showing 21-24 of 24 results.

A085619 Number of 2-graphs with n nodes and integral spectrum.

Original entry on oeis.org

2, 2, 4, 8, 9, 16
Offset: 4

Views

Author

N. J. A. Sloane, Jul 11 2003

Keywords

Links

  • F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.
  • F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.

Crossrefs

Cf. A002854.

A085620 Number of 2-graphs with n nodes and transitive automorphism group.

Original entry on oeis.org

2, 2, 4, 8, 9, 16
Offset: 4

Views

Author

N. J. A. Sloane, Jul 11 2003

Keywords

Links

  • F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.
  • F. C. Bussemaker, R. A. Mathon and J. J. Seidel, Tables of two-graphs, T.H.-Report 79-WSK-05, Technological University Eindhoven, Dept. Mathematics, 1979; also pp. 71-112 of "Combinatorics and Graph Theory (Calcutta, 1980)", Lect. Notes Math. 885, 1981.

Crossrefs

Cf. A002854.

A006536 Switching classes of digraphs.

Original entry on oeis.org

2, 6, 38, 684, 50224, 13946352, 14061131152, 50947324188128, 666754350781269760, 31763991166456912086656, 5550343429517595744902558208, 3581353054755185129132443153728000
Offset: 1

Views

Author

N. J. A. Sloane

Keywords

References

  • R. C. Read, personal communication.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A002854, A049313.

Extensions

More terms from Vladeta Jovovic, Jul 22 2000

A189771 Number of simple graphs on n nodes that are Euler (all nodes even) but not Eulerian (single cycle passes through all edges).

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 2, 7, 20, 76, 334, 2498, 36398, 1225629, 89060804, 12978995815, 3646305137905, 1947685504386516, 1969840087225045340, 3770491704215436784514, 13674048211165798257589446, 94122727377410134768239226418
Offset: 1

Views

Author

Eric W. Weisstein, Apr 26 2011

Keywords

Comments

There are more Euler graphs than Eulerian graphs since there exist disconnected graphs having multiple disjoint cycles with each node even but for which no single cycle passes through all edges.

Links

Crossrefs

Cf. A002854, A133736.

Formula

a(n) = A002854(n) - A133736(n).
Previous Showing 21-24 of 24 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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