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 A013901 #19 Sep 08 2022 08:44:38 %S A013901 194481,794280046581,3243919932521508681,13248496640331026125580781, %T A013901 54108198377272584130510593262881, %U A013901 220983347100817338120002444455525554981,902518308877795191433240103403256374623457081,3685975927806112219127687339549342762856035687969181 %N A013901 a(n) = 21^(5*n + 4). %H A013901 Vincenzo Librandi, <a href="/A013901/b013901.txt">Table of n, a(n) for n = 0..50</a> %H A013901 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013901 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (4084101). %F A013901 a(n) = 4084101*a(n-1), a(0)=194481. - _Vincenzo Librandi_, May 27 2011 %t A013901 NestList[4084101#&,194481,10] (* _Harvey P. Dale_, Dec 03 2014 *) %o A013901 (Magma) [21^(5*n+4): n in [0..10]]; // _Vincenzo Librandi_, May 27 2011 %Y A013901 Cf. A009965. %K A013901 nonn %O A013901 0,1 %A A013901 _N. J. A. Sloane_