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.
%I A186715 #49 May 19 2017 02:43:16 %S A186715 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, %T A186715 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, %U A186715 5783,2,0,0,1,0,8,0,0,1,90938,131,0,0,1,0,3917,0,0,1,1620479,123859 %N A186715 Irregular triangle C(n,k)=number of connected k-regular graphs on n vertices having girth at least five. %C A186715 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 %H A186715 Jason Kimberley, <a href="/A186715/b186715.txt">Table of i, a(i) for i = 1..111 (n = 1..28)</a> %H A186715 M. Meringer, <a href="http://www.mathe2.uni-bayreuth.de/markus/reggraphs.html">Tables of Regular Graphs</a> %H A186715 M. Meringer, <a href="http://dx.doi.org/10.1002/(SICI)1097-0118(199902)30:2<137::AID-JGT7>3.0.CO;2-G">Fast generation of regular graphs and construction of cages</a>, J. Graph Theory 30 (2) (1999) 137-146. [_Jason Kimberley_, Jan 29 2011] %H A186715 Jason Kimberley, <a href="/A186715/a186715.txt">Partial table of i, a(i) for i = 1..137 (n = 1..33)</a> %H A186715 Jason Kimberley, <a href="/A186715/a186715_2.txt">Partial table of i, n, k, a(i)=C(n,k) for n = 1..33</a> %H A186715 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/C_girth_ge_5">Connected regular graphs with girth at least 5</a> %H A186715 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/C_k-reg_girth_ge_g_index">Index of sequences counting connected k-regular simple graphs with girth at least g</a> %e A186715 01: 1; %e A186715 02: 0, 1; %e A186715 03: 0, 0; %e A186715 04: 0, 0; %e A186715 05: 0, 0, 1; %e A186715 06: 0, 0, 1; %e A186715 07: 0, 0, 1; %e A186715 08: 0, 0, 1; %e A186715 09: 0, 0, 1; %e A186715 10: 0, 0, 1, 1; %e A186715 11: 0, 0, 1, 0; %e A186715 12: 0, 0, 1, 2; %e A186715 13: 0, 0, 1, 0; %e A186715 14: 0, 0, 1, 9; %e A186715 15: 0, 0, 1, 0; %e A186715 16: 0, 0, 1, 49; %e A186715 17: 0, 0, 1, 0; %e A186715 18: 0, 0, 1, 455; %e A186715 19: 0, 0, 1, 0, 1; %e A186715 20: 0, 0, 1, 5783, 2; %e A186715 21: 0, 0, 1, 0, 8; %e A186715 22: 0, 0, 1, 90938, 131; %e A186715 23: 0, 0, 1, 0, 3917; %e A186715 24: 0, 0, 1, 1620479, 123859; %e A186715 25: 0, 0, 1, 0, 4131991; %e A186715 26: 0, 0, 1, 31478584, 132160608; %e A186715 27: 0, 0, 1, 0, 4018022149; %e A186715 28: 0, 0, 1, 656783890, 118369811960; %Y A186715 The row sums are given by A186725. %Y A186715 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). %Y A186715 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). %Y A186715 Triangular arrays C(n,k) counting connected simple k-regular graphs on n vertices with girth exactly g: A186733 (g=3), A186734 (g=4). %K A186715 nonn,hard,tabf %O A186715 1,34 %A A186715 _Jason Kimberley_, Oct 17 2011