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 A013900 #17 Sep 08 2022 08:44:38 %S A013900 9261,37822859361,154472377739119461,630880792396715529789561, %T A013900 2576580875108218291929075869661, %U A013900 10523016528610349434285830688358359761,42977062327514056734916195400155065458259861,175522663228862486625127968549968702993144556569961 %N A013900 a(n) = 21^(5*n + 3). %H A013900 Vincenzo Librandi, <a href="/A013900/b013900.txt">Table of n, a(n) for n = 0..50</a> %H A013900 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013900 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (4084101). %F A013900 a(n) = 4084101*a(n-1), a(0)=9261. - _Vincenzo Librandi_, May 27 2011 %o A013900 (Magma) [21^(5*n+3): n in [0..10]]; // _Vincenzo Librandi_, May 27 2011 %Y A013900 Cf. A009965. %K A013900 nonn %O A013900 0,1 %A A013900 _N. J. A. Sloane_