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 A010860 #26 Dec 27 2021 21:49:41 %S A010860 21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21, %T A010860 21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21, %U A010860 21,21,21,21,21,21,21,21 %N A010860 Constant sequence: a(n) = 21. %H A010860 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A010860 <a href="/index/Di#divseq">Index to divisibility sequences</a> %H A010860 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1). %F A010860 G.f.: 21/(1-x); e.g.f.: 21*e^x. - _Vincenzo Librandi_, Jan 24 2012 %K A010860 nonn,easy %O A010860 0,1 %A A010860 _N. J. A. Sloane_