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A184951 Irregular triangle C(n,g) counting the connected 5-regular simple graphs on 2n vertices with girth at least g. 7
1, 3, 60, 1, 7848, 1, 3459383, 7, 2585136675, 388, 2807105250897, 406824 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

COMMENTS

The first column is for girth at least 3. The row length sequence starts: 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4. The row length is incremented to g-2 when 2n reaches A054760(5,g).

LINKS

Table of n, a(n) for n=3..14.

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

EXAMPLE

1;

3;

60, 1;

7848, 1;

3459383, 7;

2585136675, 388;

2807105250897, 406824;

CROSSREFS

Connected 5-regular simple graphs with girth at least g: this sequence (triangle); chosen g: A006821 (g=3), A058275 (g=4), A205295 (g=5).

Connected 5-regular simple graphs with girth exactly g: A184950 (triangle); chosen g: A184953 (g=3), A184954 (g=4), A184955 (g=5).

Triangular arrays C(n,g) counting connected simple k-regular graphs on n vertices with girth at least g: A185131 (k=3), A184941 (k=4), this sequence (k=5), A184961 (k=6), A184971 (k=7), A184981 (k=8).

Sequence in context: A215609 A201184 A046024 * A081853 A183286 A195560

Adjacent sequences:  A184948 A184949 A184950 * A184952 A184953 A184954

KEYWORD

nonn,hard,more,tabf

AUTHOR

Jason Kimberley, Jan 10 2012

EXTENSIONS

a(14) from Jason Kimberley, Dec 26 2012

STATUS

approved

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Last modified November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)