A185214 Number of disconnected regular simple graphs on n vertices with girth at least 4.

0, 0, 1, 1, 2, 1, 2, 1, 3, 2, 4, 3, 7, 5, 10, 8, 22, 12, 54, 20, 218, 62, 1436, 1731, 27810, 197981, 2613814, 33117962, 463707741, 6709514340, 102306352539, 1597440872801

Offset

0,5

Links

Table of n, a(n) for n=0..31.

Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth at least g

Crossrefs

This sequence is the row sum sequence of A185204.

Regular graphs, of any degree, with girth at least 4: A186724 (connected), this sequence (disconnected), A185314 (not necessarily connected).

Disconnected k-regular simple graphs with girth at least 4: this sequence (any k), A185204 (triangle); specified degree k: A185224 (k=2), A185234 (k=3), A185244 (k=4), A185254 (k=5), A185264 (k=6), A185274 (k=7), A185284 (k=8), A185294 (k=9).

Sequence in context: A161257 A161282 A226517 * A241719 A269572 A029198

Adjacent sequences: A185211 A185212 A185213 * A185215 A185216 A185217

Keyword

nonn,more,hard

Author

Jason Kimberley, Mar 26 2012

Extensions

a(31) corrected by the author, propagated from A185244, Jan 05 2013

Status

approved