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 A185143 #23 Mar 17 2020 12:11:46 %S A185143 0,0,0,0,0,1,1,2,5,16,58,264,1535,10755,87973,803973,8020967,86029760, %T A185143 983431053,11913921910,152352965278,2050065073002,28951233955602, %U A185143 428086557232387 %N A185143 Number of not necessarily connected 4-regular simple graphs on n vertices with girth exactly 3. %H A185143 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 A185143 a(n) = A033301(n) - A185344(n). %F A185143 a(n) = A184943(n) + A185043(n). %Y A185143 4-regular simple graphs with girth exactly 3: A184943 (connected), A185043 (disconnected), this sequence (not necessarily connected). %Y A185143 Not necessarily connected k-regular simple graphs girth exactly 3: A198313 (any k), A185643 (triangle); fixed k: A026796 (k=2), A185133 (k=3), this sequence (k=4), A185153 (k=5), A185163 (k=6). %Y A185143 Not necessarily connected 4-regular simple graphs with girth exactly g: A185140 (triangle); fixed g: this sequence (g=3), A185144 (g=4). %K A185143 nonn,hard,more %O A185143 0,8 %A A185143 _Jason Kimberley_, Mar 12 2012 %E A185143 a(22) corrected and a(23) appended, due to the correction and extension of A033301 by _Andrew Howroyd_, from _Jason Kimberley_, Mar 14 2020