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 A128236 #6 Aug 15 2019 16:40:35 %S A128236 1,4,20,118,937,11936,272771,11992996,1018892793,165089910412, %T A128236 50502010570950,29054155189364119,31426485955571756316, %U A128236 64001015703946097640927,245935864153501211843554826 %N A128236 Number of n-node (unlabeled) graphs with girth 3. %Y A128236 a(n) = A000088(n) - A006785(n). %Y A128236 Cf. A128041, A128042, A128237-A128243. %K A128236 nonn %O A128236 3,2 %A A128236 _Keith Briggs_, May 05 2007 %E A128236 Corrected and extended by _Martin Fuller_, May 01 2015