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 A185044 #22 May 01 2014 02:39:58 %S A185044 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,2,2,15,35,247,1692,17409,197924, %T A185044 2492824,33117880,461597957,6709514218,101153412903,1597440868898 %N A185044 Number of disconnected 4-regular simple graphs on n vertices with girth exactly 4. %C A185044 Only one component need have girth exactly four; the other components need only have girth at least four. %C A185044 First differs from A185244 at n = 38, the smallest n where A185245 is nonzero. %H A185044 Jason Kimberley, <a href="/wiki/User:Jason_Kimberley/D_k-reg_girth_eq_g_index">Index of sequences counting disconnected k-regular simple graphs with girth exactly g</a> %F A185044 a(n) = A185244(n) - A185245(n). %F A185044 a(n) = A185144(n) - A184944(n). %Y A185044 Disconnected 4-regular simple graphs with girth exactly g: A185043 (g=3), this sequence (g=4). %Y A185044 Disconnected k-regular simple graphs with girth exactly 4: A185034 (k=3), this sequence (k=4). %K A185044 nonn,hard,more %O A185044 0,19 %A A185044 _Jason Kimberley_, Nov 04 2011 %E A185044 a(31) corrected by the author, propagated from A185244, Jan 05 2013