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 A323998 #5 Feb 14 2019 22:40:36
%S A323998 1,3,144,945,51840,2851200,174356582400,112086374400
%N A323998 Denominators of coefficients for central differences M_{5}'^(2*n+1).
%H A323998 H. E. Salzer, <a href="https://doi.org/10.1002/sapm1963421162">Tables of coefficients for obtaining central differences from the derivatives</a>, Journal of Mathematics and Physics (this journal is also called Studies in Applied Mathematics), 42 (1963), 162-165, plus several inserted tables.
%H A323998 H. E. Salzer, <a href="/A002677/a002677.png">Annotated scanned copy of left side of Table III</a>
%Y A323998 Numerators are A323997.
%K A323998 nonn,frac,more
%O A323998 2,2
%A A323998 _N. J. A. Sloane_, Feb 14 2019