A185219 Number of disconnected regular simple graphs on n vertices with girth at least 9.

0, 0, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 3, 2, 4, 3, 5, 4, 6, 5, 7, 7, 9, 9, 12, 12, 15, 16, 19, 20, 25, 26, 31, 34, 40, 43, 51, 55, 64, 71, 81, 89, 103, 113, 129, 143, 162, 179, 204, 225, 254, 282, 317, 351, 396, 437, 490, 544, 608, 673, 753, 832, 928, 1028, 1144, 1264

Offset

0,5

Links

Jason Kimberley, Table of n, a(n) for n = 0..116

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

Example

a(116) = 89574 because there is 1 such 0-regular graph (116 disconnected vertices), 1 such 1-regular graph (58 loose edges), A185229(116) = 89401, and 171 such 3-regular graphs (because A210709(58)=18).

Crossrefs

Disconnected regular graphs with girth at least g: A068932 (g=3), A185214 (g=4), A185215 (g=5), A185216 (g=6), A185217 (g=7), A185218 (g=8), this sequence (g=9).

Sequence in context: A161063 A161267 A161292 * A363828 A161319 A161253

Adjacent sequences: A185216 A185217 A185218 * A185220 A185221 A185222

Keyword

nonn,hard

Author

Jason Kimberley, Dec 19 2012

Status

approved