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 11-15 of 15 results.

A360867 Number of unlabeled connected loopless multigraphs with n edges and degree >= 3 at each node.

Original entry on oeis.org

0, 0, 1, 1, 2, 6, 12, 32, 92, 273, 869, 2989, 10722, 40599
Offset: 1

Views

Author

Andrew Howroyd, Feb 24 2023

Keywords

Crossrefs

Row sums of A360866.
Cf. A076864, A360863 (loops allowed), A360868, A360869 (not necessarily connected).

Formula

Inverse Euler transform of A360869.

A289988 Number of unlabeled connected loopless multigraphs with n nodes of degree n or less.

Original entry on oeis.org

1, 1, 2, 4, 37, 602, 34126, 6021463, 3616906549, 7361925161868, 51324462383008758, 1240420936122453106498, 105141919479926837860474091, 31581183353539008502807807352728
Offset: 0

Views

Author

Natan Arie Consigli, Aug 19 2017

Keywords

Comments

Multigraphs are loopless.

Crossrefs

Main diagonal of A334546.

Programs

  • nauty
    for n in {1..8}; do geng -c -D${n} ${n} -q | multig -m$[${n}-1] -D$[${n}-1] -u; done

Extensions

a(0) corrected and a(9)-a(13) from Andrew Howroyd, May 05 2020

A307317 Number of unlabeled connected leafless loopless multigraphs with n edges.

Original entry on oeis.org

1, 0, 1, 2, 4, 9, 26, 68, 217, 718, 2553, 9574, 38005, 157306, 679682, 3047699, 14150278, 67844305, 335262807, 1704500229, 8902528600, 47704608478, 261960998230, 1472618327415, 8466681788462, 49743177379613, 298407523833717, 1826531247381194, 11399711132242500, 72500116125222893, 469578870456459042
Offset: 0

Views

Author

Eric M. Metodiev, Apr 02 2019

Keywords

Comments

Connected multigraphs with no loops and no vertices of degree 1.
The initial terms were computed with Nauty.

Examples

			For n=3 the multigraphs (as sets of edges) are {(0,1),(0,1),(0,1)} and {(0,1),(0,2),(1,2)}.
		

Crossrefs

Cf. A076864, A307316 (not necessarily connected), A342556 (simple graphs).

Formula

Inverse Euler transform of A307316.

Extensions

a(0)=1 prepended and a(17) onwards from Andrew Howroyd, Feb 01 2024

A076865 Inverse Euler transform of 1, 1, 3, 8, 23, ... (A050535).

Original entry on oeis.org

1, 0, 2, 5, 15, 40, 136, 429, 1544, 5686, 22265, 90714, 386298, 1705828, 7806446, 36899178, 179843447, 902128265, 4650549252, 24604524692, 133442382601, 741107102344, 4210787843737, 24454774814641, 145056183186691, 878136807089527
Offset: 0

Views

Author

N. J. A. Sloane, Nov 23 2002

Keywords

Crossrefs

Extensions

More terms from Alois P. Heinz, Feb 20 2017

A076866 Euler transform of 1, 1, 3, 8, 23, ... (A050535).

Original entry on oeis.org

1, 2, 5, 14, 40, 121, 383, 1255, 4298, 15340, 57061, 221205, 893281, 3752361, 16375447, 74113910, 347258809, 1681355627, 8397528329, 43191571794, 228416030275, 1240264188677, 6905550017714, 39379283772943, 229752403826530
Offset: 0

Views

Author

N. J. A. Sloane, Nov 23 2002

Keywords

Crossrefs

Extensions

More terms from Vaclav Kotesovec, May 31 2019
Previous Showing 11-15 of 15 results.