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 A003191 M4318 #15 Jan 31 2022 01:20:35 %S A003191 1,1,6,5972,1225533120 %N A003191 Number of symmetric Latin squares of order 2n with constant diagonal. %D A003191 N. T. Gridgeman, Latin squares under restriction and a jumboization, J. Rec. Math., 5 (No. 3, 1972), 198-202. %D A003191 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A003191 <a href="/index/La#Latin">Index entries for sequences related to Latin squares and rectangles</a> %K A003191 nonn,hard,nice %O A003191 1,3 %A A003191 _N. J. A. Sloane_ %E A003191 Daniele Degiorgi (degiorgi(AT)inf.ethz.ch) suggests that this is an erroneous version of A000438.