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 A013897 #24 Jul 13 2025 12:06:32 %S A013897 160000,512000000000,1638400000000000000,5242880000000000000000000, %T A013897 16777216000000000000000000000000, %U A013897 53687091200000000000000000000000000000,171798691840000000000000000000000000000000000,549755813888000000000000000000000000000000000000000 %N A013897 a(n) = 20^(5*n + 4). %H A013897 Vincenzo Librandi, <a href="/A013897/b013897.txt">Table of n, a(n) for n = 0..50</a> %H A013897 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A013897 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (3200000). %F A013897 a(n) = 3200000*a(n-1), a(0)=160000. - _Vincenzo Librandi_, May 27 2011 %F A013897 From _Elmo R. Oliveira_, Jul 11 2025: (Start) %F A013897 G.f.: 160000/(1-3200000*x). %F A013897 E.g.f.: 160000*exp(3200000*x). %F A013897 a(n) = A013825(n)*A013857(n) = A009964(A016897(n)). (End) %t A013897 20^(5*Range[0,10]+4) (* or *) NestList[3200000#&,160000,10] (* _Harvey P. Dale_, Feb 15 2016 *) %o A013897 (Magma) [20^(5*n+4): n in [0..10]]; // _Vincenzo Librandi_, May 27 2011 %Y A013897 Subsequence of A009964. %Y A013897 Cf. A013825, A013857, A016897. %K A013897 nonn,easy %O A013897 0,1 %A A013897 _N. J. A. Sloane_