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 A306784 #13 Mar 09 2019 20:25:27
%S A306784 2,6,46,664,28129,3522087
%N A306784 Number of distinct eigenvalues of n X n matrices with elements {0, 1}.
%H A306784 S. E. Thornton, <a href="http://www.bohemianmatrices.com/cpdb/unstructured/unstructured_0_1">Properties of the Bohemian family of n x n matrices with population {0, 1}</a>, Characteristic Polynomial Database.
%Y A306784 Number of characteristic polynomials is in A272661.
%K A306784 nonn,more,hard
%O A306784 1,1
%A A306784 _Steven E. Thornton_, Mar 09 2019