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 A341852 #8 Mar 14 2021 00:47:05 %S A341852 1,3,16,132,2016,44928,1551744,68542848,4211122176,309852407808, %T A341852 29839376553984,3304540891072512,460231661327007744, %U A341852 71669823905083834368,13644939814369185890304,2845529932444144841981952,710399582113730769218174976,191237460565395319832268767232 %N A341852 Number of perfect matchings in the 4 X n rook graph. %H A341852 Andrew Howroyd, <a href="/A341852/b341852.txt">Table of n, a(n) for n = 0..50</a> %Y A341852 Row n=4 of A341850. %K A341852 nonn %O A341852 0,2 %A A341852 _Andrew Howroyd_, Feb 21 2021