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 A049526 #11 Mar 04 2021 07:23:01
%S A049526 2,6,22,94,458,2512,15354,103436,758848
%N A049526 Number of possible sets {{row sums}, {column sums}} of a 2n X 2n matrix with entries from {0,1,-1} and all row and column sums distinct.
%C A049526 It is known that such matrices of size (2n+1) X (2n+1) do not exist.
%Y A049526 Cf. A049475, A049527.
%K A049526 nonn,nice,hard,more
%O A049526 1,1
%A A049526 _Michael Kleber_