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 A013886 #23 Aug 16 2023 08:19:22 %S A013886 18,34012224,64268410079232,121439531096594251776, %T A013886 229468251895129407139872768,433595865796975883590475106484224, %U A013886 819308872942260126404286866009182175232,1548139828427760582529495524831238344488779776,2925315479322586708409093799864313376118974623776768 %N A013886 a(n) = 18^(5*n + 1). %H A013886 Vincenzo Librandi, <a href="/A013886/b013886.txt">Table of n, a(n) for n = 0..50</a> %H A013886 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013886 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1889568). %F A013886 a(n) = 1889568*a(n-1), a(0)=18. - _Vincenzo Librandi_, May 27 2011 %t A013886 18^(5*Range[0,20]+1) (* or *) NestList[1889568#&,18,10] (* _Harvey P. Dale_, Oct 29 2016 *) %o A013886 (Magma) [18^(5*n+1): n in [0..10]]; // _Vincenzo Librandi_, May 27 2011 %o A013886 (PARI) a(n) = 18^(5*n+1); \\ _Seiichi Manyama_, Aug 15 2023 %Y A013886 Cf. A001027. %K A013886 nonn %O A013886 0,1 %A A013886 _N. J. A. Sloane_