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.

A058337 Number of connected loop-free Eulerian digraphs with n nodes.

Original entry on oeis.org

1, 1, 1, 3, 12, 90, 2162, 179098, 51110788, 48762860958, 157117982629089, 1735975636147643118, 66687671220840028265672, 9012793558387399546070260538, 4328655012123103085159161399497333, 7451986601800967792474321528025564017244, 46329541711597124247394557123740768918978380463
Offset: 0

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Author

N. J. A. Sloane

Keywords

Comments

Parallel edges are not allowed, but 2-cycles are allowed. Since these digraphs have an Eulerian circuit, being weakly-connected is the same as being strongly-connected. - Brendan McKay, Apr 04 2023

References

  • F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 219 (but there is an error).
  • Ronald C. Read, email to N. J. A. Sloane, 28 August, 2000.

Links

Crossrefs

Cf. A058338.

Formula

Inverse Euler transform of A058338. - Andrew Howroyd, Apr 12 2020

Extensions

a(7) (generated graphs with nauty, filtered and counted with Python) by Pietro Battiston, Feb 08 2014
a(8) and a(9) added and description clarified by Brendan McKay, May 05 2019
Terms a(10) and beyond from Andrew Howroyd, Apr 12 2020

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

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