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