A185226 Number of disconnected 2-regular simple graphs on n vertices with girth at least 6.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 5, 5, 7, 8, 10, 11, 15, 16, 20, 23, 28, 31, 39, 43, 52, 59, 70, 79, 95, 106, 125, 142, 166, 187, 220, 247, 287, 325, 375, 423, 490, 551, 633, 715, 818, 921, 1055, 1186, 1352, 1522, 1729, 1943, 2208

Offset: 0

Author

Jason Kimberley, Feb 22 2011

Keywords

• nonn
• easy

Comments

Number of partitions of n with each part at least 6, and at least 2 parts.

Links

• Jason Kimberley, Disconnected regular graphs with girth at least 6
• Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth at least g

Crossrefs

Disconnected k-regular simple graphs with girth at least 6: A185216 (all k), A185206 (triangle); this sequence (k=2), A185236 (k=3), A185246 (k=4).

Disconnected 2-regular simple graphs with girth at least g: A165652 (g=3), A185224 (g=4), A185225 (g=5), this sequence (g=6), A185227 (g=7), A185228 (g=8), A185229 (g=9).

Programs

Magma

A185226 := func;

Formula

a(n) = A185326(n) - A185116(n).