A289987 Number of unlabeled connected loopless multigraphs with n nodes of degree less than n.

0, 1, 1, 2, 12, 146, 5847, 716141, 300635753, 430472002801, 2117649544384420, 36154420408979339192, 2165755991529764630384554, 459803603042851200545393118005

Offset

0,4

Comments

Multigraphs are loopless.

Links

Table of n, a(n) for n=0..13.

Example

From Gheorghe Coserea, Oct 11 2017: (Start)
For n=4 the a(4)=12 solutions are:
o--o--o--o   o==o--o--o   o--o==o--o   o==o--o==o
o--o         o==o         o==o
|  |         |  |         |  |
o--o         o--o         o==o
o--o         o==o
| /          | /
|/           |/
o--o         o--o
o---o        o--o         o--o--o
|\ /|        | /|            |
| x |        |/ |            o
|/ \|        o--o
o---o
(End)

Prog

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

Crossrefs

A diagonal of A334546.

Cf. A001349, A289988.

Sequence in context: A086928 A228551 A001927 * A105558 A322399 A293153

Adjacent sequences: A289984 A289985 A289986 * A289988 A289989 A289990

Keyword

nonn,more

Author

Natan Arie Consigli, Aug 19 2017

Extensions

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

Status

approved