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 A198313 #19 Feb 27 2013 09:36:09 %S A198313 0,0,0,1,1,1,4,4,15,23,162,540,18958,389417,50314520,2942196930, %T A198313 1698517018988 %N A198313 Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 3. %H A198313 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/E_k-reg_girth_eq_g_index">Index of sequences counting not necessarily connected k-regular simple graphs with girth exactly g</a> %F A198313 a(n) = A186743(n) + A210713(n). %F A198313 a(n) = A005176(n) - A185314(n). %F A198313 a(n) is the sum of the n-th row of A185643. %Y A198313 Not necessarily connected k-regular simple graphs girth exactly 3: this sequence (any k), A185643 (triangle); fixed k: A026796 (k=2), A185133 (k=3), A185143 (k=4), A185153 (k=5), A185163 (k=6). %Y A198313 Not necessarily connected regular simple graphs girth exactly g: this sequence (g=3), A198314 (g=4), A198315 (g=5), A198316 (g=6), A198317 (g=7), A198318 (g=8). %K A198313 nonn,more,hard %O A198313 0,7 %A A198313 _Jason Kimberley_, May 24 2012