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 A013895 #20 Jul 16 2025 00:57:26
%S A013895 400,1280000000,4096000000000000,13107200000000000000000,
%T A013895 41943040000000000000000000000,134217728000000000000000000000000000,
%U A013895 429496729600000000000000000000000000000000,1374389534720000000000000000000000000000000000000
%N A013895 a(n) = 20^(5*n + 2).
%H A013895 Vincenzo Librandi, <a href="/A013895/b013895.txt">Table of n, a(n) for n = 0..50</a>
%H A013895 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>.
%H A013895 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (3200000).
%F A013895 a(n) = 3200000*a(n-1), a(0)=400. - _Vincenzo Librandi_, May 27 2011
%F A013895 G.f.: -400/(3200000*x-1). - _Colin Barker_, Nov 17 2015
%F A013895 a(n) = A009964(A016873(n)). - _Wesley Ivan Hurt_, Nov 17 2015
%F A013895 From _Elmo R. Oliveira_, Jul 13 2025: (Start)
%F A013895 E.g.f.: 400*exp(3200000*x).
%F A013895 a(n) = 20*A013894(n) = A013896(n)/20 = A013823(n)*A013855(n). (End)
%p A013895 A013895:=n->20^(5*n+2): seq(A013895(n), n=0..10); # _Wesley Ivan Hurt_, Nov 17 2015
%t A013895 20^(5 Range[0, 10] + 2) (* or *) CoefficientList[Series[-400/(3200000*x - 1), {x, 0, 10}], x] (* _Wesley Ivan Hurt_, Nov 17 2015 *)
%o A013895 (Magma) [20^(5*n+2): n in [0..10]]; // _Vincenzo Librandi_, May 27 2011
%o A013895 (PARI) Vec(-400/(3200000*x-1) + O(x^10)) \\ _Colin Barker_, Nov 17 2015
%Y A013895 Subsequence of A009964.
%Y A013895 Cf. A013823, A013855, A013894, A013896, A016873.
%K A013895 nonn,easy
%O A013895 0,1
%A A013895 _N. J. A. Sloane_