A185131 Irregular triangle C(n,g) counting connected trivalent simple graphs on 2n vertices with girth at least g.
1, 2, 1, 5, 2, 19, 6, 1, 85, 22, 2, 509, 110, 9, 1, 4060, 792, 49, 1, 41301, 7805, 455, 5, 510489, 97546, 5783, 32, 7319447, 1435720, 90938, 385, 117940535, 23780814, 1620479, 7574, 1, 2094480864, 432757568, 31478584, 181227, 3, 40497138011, 8542471494
Offset: 2
Examples
1; 2, 1; 5, 2; 19, 6, 1; 85, 22, 2; 509, 110, 9, 1; 4060, 792, 49, 1; 41301, 7805, 455, 5; 510489, 97546, 5783, 32; 7319447, 1435720, 90938, 385; 117940535, 23780814, 1620479, 7574, 1; 2094480864, 432757568, 31478584, 181227, 3; 40497138011, 8542471494, 656783890, 4624501, 21; 845480228069, 181492137812, 14621871204, 122090544, 546, 1; 18941522184590, 4127077143862, 345975648562, 3328929954, 30368, 0; 453090162062723, ?, ?, 93990692595, 1782840, 1; 11523392072541432, ?, ?, 2754222605376, 95079083, 3; 310467244165539782, ?, ?, ?, 4686063120, 13; 8832736318937756165, ?, ?, ?, 220323447962, 155; ?, ?, ?, ?, 10090653722861, 4337;
Links
- Jason Kimberley, Table of i, a(i) for i = 2..59 (n = 2..16)
- B. Brinkmann, J. Goedgebeur, and B. D. McKay, Generation of cubic graphs, Discr. Math. Theor. Comp. Sci. 13 (2) (2011) 69-80.
- House of Graphs, Cubic graphs
- Jason Kimberley, Index of sequences counting connected k-regular simple graphs with girth at least g
- M. Meringer, Tables of Regular Graphs
Crossrefs
Connected 3-regular simple graphs with girth at least g: this sequence (triangle); chosen g: A002851 (g=3), A014371 (g=4), A014372 (g=5), A014374 (g=6), A014375 (g=7), A014376 (g=8).
Extensions
Terms C(18,6), C(20,7) and C(21,7) from House of Graphs via Jason Kimberley, May 21 2017
Comments