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A319612
Number of regular simple graphs spanning n vertices.
14
1, 0, 1, 1, 7, 13, 171, 931, 45935, 1084413, 155862511, 10382960971, 6939278572095, 2203360500122299, 4186526756621772343, 3747344008241368443819, 35041787059691023579970847, 156277111373303386104606663421, 4142122641757598618318165240180095
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OFFSET
0,5
COMMENTS
A graph is regular if all vertices have the same degree. The span of a graph is the union of its edges.
LINKS
Table of n, a(n) for n=0..18.
FORMULA
a(n) =
A295193
(n) - 1.
EXAMPLE
The a(4) = 7 edge-sets:
{{1,2},{3,4}}
{{1,3},{2,4}}
{{1,4},{2,3}}
{{1,2},{1,3},{2,4},{3,4}}
{{1,2},{1,4},{2,3},{3,4}}
{{1,3},{1,4},{2,3},{2,4}}
{{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}}
CROSSREFS
Cf.
A002829
,
A005176
,
A110100
,
A116539
,
A295193
,
A306017
,
A319189
,
A319190
.
Sequence in context:
A342717
A050946
A178956
*
A247946
A210465
A181492
Adjacent sequences:
A319609
A319610
A319611
*
A319613
A319614
A319615
KEYWORD
nonn
AUTHOR
Gus Wiseman
, Dec 17 2018
EXTENSIONS
a(16)-a(18) from
Andrew Howroyd
, Sep 02 2019
STATUS
approved
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Last modified July 12 16:06 EDT 2024. Contains 374251 sequences. (Running on oeis4.)