A185364 - OEIS

A185364

Not necessarily connected 6-regular simple graphs on n vertices with girth at least 4.

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 9, 6, 267, 3727, 483012, 69823723, 14836130862

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

OFFSET

0,17

COMMENTS

First differs from A058276 at n=24.

LINKS

Table of n, a(n) for n=0..22.

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 A058276.

a(n) = A058276(n) + A185264(n).

MATHEMATICA

A058276 = Cases[Import["https://oeis.org/A058276/b058276.txt", "Table"], {_, _}][[All, 2]];

(* EulerTransform is defined in A005195 *)

EulerTransform[Rest @ A058276] (* Jean-François Alcover, Dec 04 2019, updated Mar 18 2020 *)

CROSSREFS

6-regular simple graphs with girth at least 4: A058276 (connected), A185264 (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), A185354 (k=5), this sequence (k=6).

Sequence in context: A038296 A058276 A184964 * A085678 A256687 A086819

Adjacent sequences: A185361 A185362 A185363 * A185365 A185366 A185367

KEYWORD

nonn,more,hard

AUTHOR

Jason Kimberley, Dec 07 2011

STATUS

approved