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 A013781 #24 Sep 08 2022 08:44:38 %S A013781 64,16384,4194304,1073741824,274877906944,70368744177664, %T A013781 18014398509481984,4611686018427387904,1180591620717411303424, %U A013781 302231454903657293676544,77371252455336267181195264,19807040628566084398385987584 %N A013781 a(n) = 4^(4*n + 3). %H A013781 Vincenzo Librandi, <a href="/A013781/b013781.txt">Table of n, a(n) for n = 0..100</a> %H A013781 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a> %H A013781 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (256). %F A013781 From _Philippe Deléham_, Nov 27 2008: (Start) %F A013781 a(n) = 256*a(n-1); a(0)=64. %F A013781 G.f.: 64/(1-256*x). %F A013781 a(n) = 4*A013721(n). (End) %o A013781 (Magma) [4^(4*n+3): n in [0..15]]; // _Vincenzo Librandi_, Jun 04 2011 %o A013781 (Maxima) makelist(4^(4*n+3),n,0,20); /* _Martin Ettl_, Oct 21 2012 */ %o A013781 (PARI) a(n) = 4^(4*n+3); \\ _Altug Alkan_, Sep 08 2018 %Y A013781 Cf. A013721. %K A013781 nonn %O A013781 0,1 %A A013781 _N. J. A. Sloane_