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 A023047 #14 Feb 22 2019 08:43:44 %S A023047 1334961,16019531,206918942,2864826126,42351635064,666166856520, %T A023047 11113078385520,196038409800240,3646938237505920,71370457471716480, %U A023047 1465957162768492800,31537353006189676800,709233590351909145600,16643157932371543372800,406858911634713765427200 %N A023047 10th differences of factorial numbers. %H A023047 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a> %t A023047 Differences[Range[0,25]!,10] (* _Harvey P. Dale_, May 25 2011 *) %K A023047 nonn %O A023047 0,1 %A A023047 _David W. Wilson_