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 A239739 #18 Sep 08 2022 08:46:07
%S A239739 0,64,2048,49152,1048576,20971520,402653184,7516192768,137438953472,
%T A239739 2473901162496,43980465111040,774056185954304,13510798882111488,
%U A239739 234187180623265792,4035225266123964416,69175290276410818560,1180591620717411303424,20070057552195992158208
%N A239739 a(n) = n*4^(2*n+1).
%C A239739 Appears in asymptotic expansions of the logarithm of the central binomial and the Catalan numbers. (See Kessler and Schiff, page 2.)
%H A239739 Vincenzo Librandi, <a href="/A239739/b239739.txt">Table of n, a(n) for n = 0..200</a>
%H A239739 D. Kessler and J. Schiff, <a href="http://u.math.biu.ac.il/~schiff/Papers/prepap3.pdf">The asymptotics of factorials, binomial coefficients and Catalan numbers</a>. April 2006.
%H A239739 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (32,-256).
%F A239739 G.f.: 64*x / (1 - 16*x)^2. [_Bruno Berselli_, Mar 26 2014]
%F A239739 (n-1)*a(n) - 16*n*a(n-1) = 0. [_Bruno Berselli_, Mar 26 2014]
%F A239739 a(n) = n*A013709(n). - _Michel Marcus_, Jan 30 2016
%t A239739 CoefficientList[Series[64 x /(1 - 16 x)^2, {x, 0, 20}], x] (* _Vincenzo Librandi_, Apr 25 2014 *)
%t A239739 LinearRecurrence[{32,-256},{0,64},20] (* _Harvey P. Dale_, May 06 2021 *)
%o A239739 (Magma) [n*4^(2*n+1): n in [0..25]]; // _Vincenzo Librandi_, Apr 25 2014
%Y A239739 Cf. A219931, A220002, A220422, A267796, A013709.
%K A239739 nonn,easy
%O A239739 0,2
%A A239739 _Peter Luschny_, Mar 26 2014