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

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