cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 11 results. Next

A068934 Triangular array C(n, r) = number of connected r-regular graphs with n nodes, 0 <= r < n.

Original entry on oeis.org

1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 2, 1, 1, 0, 0, 1, 0, 2, 0, 1, 0, 0, 1, 5, 6, 3, 1, 1, 0, 0, 1, 0, 16, 0, 4, 0, 1, 0, 0, 1, 19, 59, 60, 21, 5, 1, 1, 0, 0, 1, 0, 265, 0, 266, 0, 6, 0, 1, 0, 0, 1, 85, 1544, 7848, 7849, 1547, 94, 9, 1, 1, 0, 0, 1, 0, 10778, 0, 367860, 0
Offset: 1

Views

Author

David Wasserman, Mar 08 2002

Keywords

Comments

A graph is called r-regular if every node has exactly r edges. The numbers in this table were copied from the column sequences.
This sequence can be derived from A051031 by inverse Euler transform. See the comments in A051031 for a brief description of how that sequence can be computed without generating all regular graphs. - Andrew Howroyd, Mar 13 2020

Examples

			01: 1;
02: 0, 1;
03: 0, 0, 1;
04: 0, 0, 1, 1;
05: 0, 0, 1, 0, 1;
06: 0, 0, 1, 2, 1, 1;
07: 0, 0, 1, 0, 2, 0, 1;
08: 0, 0, 1, 5, 6, 3, 1, 1;
09: 0, 0, 1, 0, 16, 0, 4, 0, 1;
10: 0, 0, 1, 19, 59, 60, 21, 5, 1, 1;
11: 0, 0, 1, 0, 265, 0, 266, 0, 6, 0, 1;
12: 0, 0, 1, 85, 1544, 7848, 7849, 1547, 94, 9, 1, 1;
13: 0, 0, 1, 0, 10778, 0, 367860, 0, 10786, 0, 10, 0, 1;
14: 0, 0, 1, 509, 88168, 3459383, 21609300, 21609301, 3459386, 88193, 540, 13, 1, 1;
15: 0, 0, 1, 0, 805491, 0, 1470293675, 0, 1470293676, 0, 805579, 0, 17, 0, 1;
16: 0, 0, 1, 4060, 8037418, 2585136675, 113314233808, 733351105934, 733351105935, 113314233813, 2585136741, 8037796, 4207, 21, 1, 1;
		

Crossrefs

Connected regular simple graphs: A005177 (any degree -- sum of rows), this sequence (triangular array), specified degree r (columns): A002851 (r=3), A006820 (r=4), A006821 (r=5), A006822 (r=6), A014377 (r=7), A014378 (r=8), A014381 (r=9), A014382 (r=10), A014384 (r=11).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *at least* g: this sequence (g=3), A186714 (g=4), A186715 (g=5), A186716 (g=6), A186717 (g=7), A186718 (g=8), A186719 (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *exactly* g: A186733 (g=3), A186734 (g=4).

Formula

C(n, r) = A051031(n, r) - A068933(n, r).
Column k is the inverse Euler transform of column k of A051031. - Andrew Howroyd, Mar 10 2020

Extensions

Edited by Jason Kimberley, Sep 23 2009, Nov 2011, Jan 2012, and Mar 2012

A186714 Triangular array C(n, k) = number of connected k-regular graphs, having girth at least 4, with n nodes, 0 <= k <= n div 2.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 2, 1, 0, 0, 1, 0, 0, 0, 0, 1, 6, 2, 1, 0, 0, 1, 0, 2, 0, 0, 0, 1, 22, 12, 1, 1, 0, 0, 1, 0, 31, 0, 0, 0, 0, 1, 110, 220, 7, 1, 1, 0, 0, 1, 0, 1606, 0, 1, 0, 0, 0, 1, 792, 16828, 388, 9, 1, 1, 0, 0, 1, 0, 193900, 0, 6, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Jason Kimberley, Sep 04 2011

Keywords

Examples

			01: 1;
02: 0,1;
03: 0,0;
04: 0,0,1;
05: 0,0,1;
06: 0,0,1,1;
07: 0,0,1,0;
08: 0,0,1,2,1;
09: 0,0,1,0,0;
10: 0,0,1,6,2,1;
11: 0,0,1,0,2,0;
12: 0,0,1,22,12,1,1;
13: 0,0,1,0,31,0,0;
14: 0,0,1,110,220,7,1,1;
15: 0,0,1,0,1606,0,1,0;
16: 0,0,1,792,16828,388,9,1,1;
17: 0,0,1,0,193900,0,6,0,0;
18: 0,0,1,7805,2452818,406824,267,8,1,1;
19: 0,0,1,0,32670330,0,3727,0,0,0;
20: 0,0,1,97546,456028474,1125022325,483012,741,13,1,1;
21: 0,0,1,0,6636066099,0,69823723,0,1,0,0;
22: 0,0,1,1435720,100135577747,3813549359274,14836130862,2887493,?,14,1,1;
23: 0,0,1,0,1582718912968,0,?,0,?,0,0;
		

Crossrefs

The sum of the n-th row is A186724(n).
Connected k-regular simple graphs with girth at least 4: A186724 (any k), this sequence (triangle); specified degree k: A185114 (k=2), A014371 (k=3), A033886 (k=4), A058275 (k=5), A058276 (k=6), A181153 (k=7), A181154 (k=8), A181170 (k=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *at least* g: A068934 (g=3), this sequence (g=4), A186715 (g=5), A186716 (g=6), A186717 (g=7), A186718 (g=8), A186719 (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *exactly* g: A186733 (g=3), A186734 (g=4).

A186715 Irregular triangle C(n,k)=number of connected k-regular graphs on n vertices having girth at least five.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 2, 0, 0, 1, 0, 0, 0, 1, 9, 0, 0, 1, 0, 0, 0, 1, 49, 0, 0, 1, 0, 0, 0, 1, 455, 0, 0, 1, 0, 1, 0, 0, 1, 5783, 2, 0, 0, 1, 0, 8, 0, 0, 1, 90938, 131, 0, 0, 1, 0, 3917, 0, 0, 1, 1620479, 123859
Offset: 1

Views

Author

Jason Kimberley, Oct 17 2011

Keywords

Comments

Brendan McKay has observed that C(26,3) = 31478584 is output by genreg, minibaum, and snarkhunter, but Meringer's table currently has C(26,3) = 31478582. - Jason Kimberley, May 19 2017

Examples

			01: 1;
02: 0, 1;
03: 0, 0;
04: 0, 0;
05: 0, 0, 1;
06: 0, 0, 1;
07: 0, 0, 1;
08: 0, 0, 1;
09: 0, 0, 1;
10: 0, 0, 1, 1;
11: 0, 0, 1, 0;
12: 0, 0, 1, 2;
13: 0, 0, 1, 0;
14: 0, 0, 1, 9;
15: 0, 0, 1, 0;
16: 0, 0, 1, 49;
17: 0, 0, 1, 0;
18: 0, 0, 1, 455;
19: 0, 0, 1, 0, 1;
20: 0, 0, 1, 5783, 2;
21: 0, 0, 1, 0, 8;
22: 0, 0, 1, 90938, 131;
23: 0, 0, 1, 0, 3917;
24: 0, 0, 1, 1620479, 123859;
25: 0, 0, 1, 0, 4131991;
26: 0, 0, 1, 31478584, 132160608;
27: 0, 0, 1, 0, 4018022149;
28: 0, 0, 1, 656783890, 118369811960;
		

Crossrefs

The row sums are given by A186725.
Connected k-regular simple graphs with girth at least 5: A186725 (all k), this sequence (triangle); A185115 (k=2), A014372 (k=3), A058343 (k=4), A205295 (k=5).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth at least g: A068934 (g=3), A186714 (g=4), this sequence (g=5), A186716 (g=6), A186717 (g=7), A186718 (g=8), A186719 (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4).

A186716 Irregular triangle C(n,k): the number of connected k-regular graphs on n vertices having girth at least six.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 5, 0, 0, 1, 0, 0, 0, 1, 32, 0, 0, 1, 0, 0, 0, 1, 385, 0, 0, 1, 0, 0, 0, 1, 7574, 0, 0, 1, 0, 0, 0, 1, 181227, 1, 0, 0, 1, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Jason Kimberley, Nov 23 2011

Keywords

Comments

Other than the first two rows, each row begins with 0, 0, 1.

Examples

			1;
0, 1;
0, 0;
0, 0;
0, 0;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1, 1;
0, 0, 1, 0;
0, 0, 1, 1;
0, 0, 1, 0;
0, 0, 1, 5;
0, 0, 1, 0;
0, 0, 1, 32;
0, 0, 1, 0;
0, 0, 1, 385;
0, 0, 1, 0;
0, 0, 1, 7574;
0, 0, 1, 0;
0, 0, 1, 181227, 1;
0, 0, 1, 0, 0;
0, 0, 1, 4624501, 1;
0, 0, 1, 0, 0;
0, 0, 1, 122090544, 4;
0, 0, 1, 0, 0;
0, 0, 1, 3328929954, 19;
0, 0, 1, 0, 0;
0, 0, 1, 93990692595, 1272;
0, 0, 1, 0, 25;
0, 0, 1, 2754222605376, 494031;
0, 0, 1, 0, 13504;
		

References

  • M. Meringer, Fast Generation of Regular Graphs and Construction of Cages. Journal of Graph Theory, 30 (1999), 137-146.

Crossrefs

Connected k-regular simple graphs with girth at least 6: A186726 (any k), this sequence (triangle); specific k: A185116 (k=2), A014374 (k=3), A058348 (k=4).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth at least g: A068934 (g=3), A186714 (g=4), A186715 (g=5), this sequence (g=6), A186717 (g=7), A186718 (g=8), A186719 (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4).

Extensions

C(36,3) from House of Graphs via Jason Kimberley, May 21 2017

A186717 Irregular triangle C(n,k): the number of connected k-regular graphs on n vertices having girth at least seven.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 3, 0, 0, 1, 0, 0, 0, 1, 21, 0, 0, 1, 0, 0, 0, 1, 546, 0, 0, 1, 0, 0, 0, 1, 30368
Offset: 1

Views

Author

Jason Kimberley, Nov 28 2011

Keywords

Examples

			1;
0, 1;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1, 1;
0, 0, 1, 0;
0, 0, 1, 3;
0, 0, 1, 0;
0, 0, 1, 21;
0, 0, 1, 0;
0, 0, 1, 546;
0, 0, 1, 0;
0, 0, 1, 30368;
0, 0, 1, 0;
0, 0, 1, 1782840;
0, 0, 1, 0;
0, 0, 1, 95079083;
0, 0, 1, 0;
0, 0, 1, 4686063120;
0, 0, 1, 0;
		

Crossrefs

Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth at least g: A068934 (g=3), A186714 (g=4), A186715 (g=5), A186716 (g=6), this sequence (g=7), A186718 (g=8), A186719 (g=9).
Connected k-regular simple graphs with girth at least 7: A186727 (any k), this sequence (triangle); specific k: A185117 (k=2), A014375 (k=3).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4).

A186718 Irregular triangle C(n,k): number of connected k-regular simple graphs on n vertices with girth at least eight.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 3
Offset: 1

Views

Author

Jason Kimberley, Nov 28 2011

Keywords

Examples

			1;
0, 1;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1, 1;
0, 0, 1, 0;
0, 0, 1, 0;
0, 0, 1, 0;
0, 0, 1, 1;
0, 0, 1, 0;
0, 0, 1, 3;
0, 0, 1, 0;
0, 0, 1, 13;
0, 0, 1, 0;
0, 0, 1, 155;
0, 0, 1, 0;
0, 0, 1, 4337;
0, 0, 1, 0;
0, 0, 1, 266362;
0, 0, 1, 0;
0, 0, 1, 20807688;
0, 0, 1, 0;
		

Crossrefs

Connected k-regular simple graphs with girth at least 8: A186728 (any k), this sequence (triangle); specific k: A185118 (k=2), A014376 (k=3).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth at least g: A068934 (g=3), A186714 (g=4), A186715 (g=5), A186716 (g=6), A186717 (g=7), this sequence (g=8), A186719 (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4).

A186719 Irregular triangle C(n,k): number of connected k-regular simple graphs on n vertices with girth at least nine.

Original entry on oeis.org

1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1
Offset: 1

Views

Author

Jason Kimberley, Nov 29 2011

Keywords

Examples

			1;
0, 1;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1;
0, 0, 1, 18;
		

Crossrefs

Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth at least g: A068934 (g=3), A186714 (g=4), A186715 (g=5), A186716 (g=6), A186717 (g=7), A186718 (g=8), this sequence (g=9).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4).
Connected k-regular simple graphs with girth at least 9: A186729 (all k), this sequence (triangular array), A185119 (k=2).

A186734 Triangular array C(n,k) counting connected k-regular simple graphs on n vertices with girth exactly 4.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 2, 1, 0, 0, 0, 0, 0, 0, 0, 0, 5, 2, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 20, 12, 1, 1, 0, 0, 0, 0, 31, 0, 0, 0, 0, 0, 101, 220, 7, 1, 1, 0, 0, 0, 0, 1606, 0, 1, 0, 0, 0, 0, 743, 16828, 388, 9, 1, 1, 0, 0, 0, 0, 193900, 0, 6, 0, 0, 0, 0, 0, 7350
Offset: 1

Views

Author

Jason Kimberley, Mar 20 2013

Keywords

Comments

In the n-th row 0 <= 2k <= n.

Examples

			01: 0;
02: 0, 0;
03: 0, 0;
04: 0, 0, 1;
05: 0, 0, 0;
06: 0, 0, 0, 1;
07: 0, 0, 0, 0;
08: 0, 0, 0, 2, 1;
09: 0, 0, 0, 0, 0;
10: 0, 0, 0, 5, 2, 1;
11: 0, 0, 0, 0, 2, 0;
12: 0, 0, 0, 20, 12, 1, 1;
13: 0, 0, 0, 0, 31, 0, 0;
14: 0, 0, 0, 101, 220, 7, 1, 1;
15: 0, 0, 0, 0, 1606, 0, 1, 0;
16: 0, 0, 0, 743, 16828, 388, 9, 1, 1;
17: 0, 0, 0, 0, 193900, 0, 6, 0, 0;
18: 0, 0, 0, 7350, 2452818, 406824, 267, 8, 1, 1;
19: 0, 0, 0, 0, 32670329, 0, 3727, 0, 0, 0;
20: 0, 0, 0, 91763, 456028472, 1125022325, 483012, 741, 13, 1, 1;
21: 0, 0, 0, 0, 6636066091, 0, 69823723, 0, 1, 0, 0;
		

Crossrefs

The sum of the n-th row of this sequence is A186744(n).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *exactly* g: A186733 (g=3), this sequence (g=4).
Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth *at least* g: A068934 (g=3), A186714 (g=4).

Formula

C(n,k) = A186714(n,k) - A186715(n,k), noting the differing row lengths.
E(n,k) = A185644(n,k) - A210704(n,k), noting the differing row lengths.

A185643 Triangular array E(n,k) counting, not necessarily connected, k-regular simple graphs on n vertices with girth exactly 3.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 2, 0, 1, 0, 0, 1, 4, 5, 3, 1, 1, 0, 0, 2, 0, 16, 0, 4, 0, 1, 0, 0, 2, 15, 58, 59, 21, 5, 1, 1, 0, 0, 3, 0, 264, 0, 266, 0, 6, 0, 1, 0, 0, 4, 71, 1535, 7848, 7848, 1547, 94, 9, 1, 1, 0, 0, 5, 0, 10755, 0, 367860, 0, 10786, 0, 10, 0, 1
Offset: 1

Views

Author

Jason Kimberley, Feb 07 2013

Keywords

Examples

			01: 0;
02: 0, 0;
03: 0, 0, 1;
04: 0, 0, 0, 1;
05: 0, 0, 0, 0, 1;
06: 0, 0, 1, 1, 1, 1;
07: 0, 0, 1, 0, 2, 0, 1;
08: 0, 0, 1, 4, 5, 3, 1, 1;
09: 0, 0, 2, 0, 16, 0, 4, 0, 1;
10: 0, 0, 2, 15, 58, 59, 21, 5, 1, 1;
11: 0, 0, 3, 0, 264, 0, 266, 0, 6, 0, 1;
12: 0, 0, 4, 71, 1535, 7848, 7848, 1547, 94, 9, 1, 1;
13: 0, 0, 5, 0, 10755, 0, 367860, 0, 10786, 0, 10, 0, 1;
14: 0, 0, 6, 428, 87973, 3459379, 21609300, 21609300, 3459386, 88193, 540, 13, 1, 1;
15: 0, 0, 9, 0, 803973, 0, 1470293675, 0, 1470293676, 0, 805579, 0, 17, 0, 1;
16: 0, 0, 10, 3406, 8020967, 2585136353, 113314233804, 733351105934, 733351105934, 113314233813, 2585136741, 8037796, 4207, 21, 1, 1;
		

Crossrefs

The sum of the n-th row of this sequence is A198313(n).
Not necessarily connected k-regular simple graphs girth exactly 3: A198313 (any k), this sequence (triangle); fixed k: A026796 (k=2), A185133 (k=3), A185143 (k=4), A185153 (k=5), A185163 (k=6).

Formula

E(n,k) = A186733(n,k) + A210703(n,k), noting that A210703 is a tabf.
E(n,k) = A051031(n,k) - A185304(n,k), noting that A185304 is a tabf.

A210703 Triangular array D(n,k) counting disconnected k-regular simple graphs on n vertices with girth exactly 3.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 2, 0, 0, 0, 2, 2, 1, 0, 0, 3, 0, 1, 0, 0, 4, 8, 3, 1, 0, 0, 5, 0, 8, 0, 0, 0, 6, 29, 25, 3, 1, 0, 0, 9, 0, 88, 0, 1, 0, 0, 10, 138, 377, 66, 5, 1, 0, 0, 13, 0, 2026, 0, 25, 0, 0, 0, 17, 774, 13349, 8029, 297, 5, 1, 0, 0, 21, 0, 104593, 0, 8199, 0, 1, 0, 0, 25, 5678, 930571, 3484759, 377004, 1562, 7, 1
Offset: 2

Views

Author

Jason Kimberley, Jan 21 2013

Keywords

Examples

			2: 0;
3: 0;
4: 0, 0;
5: 0, 0;
6: 0, 0, 1;
7: 0, 0, 1;
8: 0, 0, 1, 1;
9: 0, 0, 2, 0;
10: 0, 0, 2, 2, 1;
11: 0, 0, 3, 0, 1;
12: 0, 0, 4, 8, 3, 1;
13: 0, 0, 5, 0, 8, 0;
14: 0, 0, 6, 29, 25, 3, 1;
15: 0, 0, 9, 0, 88, 0, 1;
16: 0, 0, 10, 138, 377, 66, 5, 1;
17: 0, 0, 13, 0, 2026, 0, 25, 0;
18: 0, 0, 17, 774, 13349, 8029, 297, 5, 1;
19: 0, 0, 21, 0, 104593, 0, 8199, 0, 1;
20: 0, 0, 25, 5678, 930571, 3484759, 377004, 1562, 7, 1;
21: 0, 0, 33, 0, 9124627, 0, 22014143, 0, 100, 0;
22: 0, 0, 39, 53324, 96699740, 2595985769, 1493574756, 21617036, 10901, 9, 1;
23: 0, 0, 49, 0, 1095467916, 0, 114880777582, 0, 3470736, 0, 1;
24: 0, 0, 60, 622716, 13175254799, 2815099031409, 9919463450854, 733460349818, 1473822243, 88238, 11, 1;
		

Crossrefs

The sum of the n-th row is A210713(n).
Disconnected k-regular simple graphs with girth exactly 3: A210713 (any k), this sequence (triangle); for a fixed k: A185033 (k=3), A185043 (k=4), A185053 (k=5), A185063 (k=6).

Formula

D(n,k) = A068933(n,k) - A185204(n,k) [the former is padded to be a tabl but the latter is a tabf].
D(n,k) = A185643(n,k) - A186733(n,k) [both are tabl but the result is tabf].
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