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A185354

Number of not necessarily connected 5-regular simple graphs on 2n vertices with girth at least 4.

1, 0, 0, 0, 0, 1, 1, 7, 388, 406824, 1125022326, 3813549359275

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,8

LINKS

Table of n, a(n) for n=0..11.

Jason Kimberley, Not necessarily connected k-regular graphs with girth at least 4

Jason Kimberley, Index of sequences counting not necessarily connected k-regular simple graphs with girth at least g

FORMULA

This sequence is the Euler transformation of A058275.

a(n) = A058275(n) + A185254(n).

MATHEMATICA

A058275 = Cases[Import["https://oeis.org/A058275/b058275.txt", "Table"], {_, _}][[All, 2]];

(* EulerTransform is defined in A005195 *)

EulerTransform[Rest @ A058275] (* Jean-François Alcover, Dec 04 2019, updated Mar 18 2020 *)

CROSSREFS

5-regular simple graphs on 2n vertices with girth at least 4: A058275 (connected), A185254 (disconnected), this sequence (not necessarily connected).

Not necessarily connected k-regular simple graphs with girth at least 4: A185314 (any k), A185304 (triangle); specified degree k: A008484 (k=2), A185334 (k=3), A185344 (k=4), this sequence (k=5), A185364 (k=6).

Sequence in context: A293459 A058275 A184954 * A222893 A009712 A128793

Adjacent sequences: A185351 A185352 A185353 * A185355 A185356 A185357

KEYWORD

hard,nonn,more

AUTHOR

Jason Kimberley, Nov 04 2011

STATUS

approved

URL: https://oeis.org/A185354

⇱ A185354 - OEIS