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 A306815 #9 Mar 12 2019 07:33:45
%S A306815 2,14,424,54966,28957764
%N A306815 Number of non-derogatory n X n matrices with elements {0, 1}.
%H A306815 Encyclopedia of Math, <a href="https://www.encyclopediaofmath.org/index.php/Non-derogatory_matrix">Non-derogatory matrix</a>
%H A306815 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 A306815 Number of characteristic polynomials is in A272661.
%Y A306815 Number of minimal polynomials is in A306781.
%K A306815 nonn,more,hard
%O A306815 1,1
%A A306815 _Steven E. Thornton_, Mar 11 2019