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 A174556 #9 Jan 30 2021 01:30:41 %S A174556 12,240,10480,535080,34634544 %N A174556 Number of 3 X n Latin rectangles whose second row contains two cycles. %H A174556 V. S. Shevelev, <a href="http://mi.mathnet.ru/eng/dm720">Reduced Latin rectangles and square matrices with equal row and column sums</a>, Diskr. Mat.(J. of the Akademy of Sciences of Russia) 4(1992), 91-110. %Y A174556 Cf. A000186, A094047. %K A174556 nonn,more,uned %O A174556 4,1 %A A174556 _Vladimir Shevelev_, Mar 22 2010