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A185226
Number of disconnected 2-regular simple graphs on n vertices with girth at least 6.
13
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
0,15
COMMENTS
Number of partitions of n with each part at least 6, and at least 2 parts.
FORMULA
a(n) = A185326(n) - A185116(n).
PROG
(Magma) A185226 := func<n|n eq 0 select 0 else #RestrictedPartitions(n, {6..n-1})>;
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).
Sequence in context: A239513 A029018 A238217 * A096765 A025147 A364613
KEYWORD
nonn,easy
AUTHOR
Jason Kimberley, Feb 22 2011
STATUS
approved