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 A013767 #28 Feb 27 2025 15:16:45 %S A013767 400,3200000,25600000000,204800000000000,1638400000000000000, %T A013767 13107200000000000000000,104857600000000000000000000, %U A013767 838860800000000000000000000000,6710886400000000000000000000000000,53687091200000000000000000000000000000,429496729600000000000000000000000000000000 %N A013767 a(n) = 20^(3*n + 2). %H A013767 Vincenzo Librandi, <a href="/A013767/b013767.txt">Table of n, a(n) for n = 0..200</a> %H A013767 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A013767 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (8000). %F A013767 From _Elmo R. Oliveira_, Feb 27 2025: (Start) %F A013767 G.f.: 400/(1 - 8000*x). %F A013767 E.g.f.: 400*exp(8000*x). %F A013767 a(n) = A013731(n)*A013747(n) = A009964(A016789(n)). (End) %t A013767 NestList[8000#&,400,10] (* _Harvey P. Dale_, May 11 2018 *) %o A013767 (Magma) [20^(3*n+2): n in [0..10]]; // _Vincenzo Librandi_, Jun 27 2011 %o A013767 (PARI) a(n)=20^(3*n+2) \\ _Charles R Greathouse IV_, Jul 10 2016 %Y A013767 Subsequence of A009964. %Y A013767 Cf. A013731, A013747, A016789. %K A013767 nonn,easy %O A013767 0,1 %A A013767 _N. J. A. Sloane_