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 A186743 #8 May 01 2014 02:40:01 %S A186743 0,0,0,1,1,1,3,3,13,21,157,536,18942,389404,50314456,2942196832, %T A186743 1698517018391 %N A186743 Number of connected regular simple graphs on n vertices with girth exactly 3. %H A186743 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/C_k-reg_girth_eq_g_index">Index of sequences counting connected k-regular simple graphs with girth exactly g</a> %F A186743 a(n) = A005177(n) - A186724(n). %Y A186743 Connected k-regular simple graphs with girth exactly 3: this sequence (any k), A186733 (triangular array); specified k: A006923 (k=3),A184943 (k=4), A184953 (k=5), A184963 (k=6), A184973 (k=7),A184983 (k=8), A184993 (k=9). %K A186743 nonn,more,hard %O A186743 0,7 %A A186743 _Jason Kimberley_, Dec 01 2011