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 A013777 #35 Jul 21 2025 08:57:30 %S A013777 8,128,2048,32768,524288,8388608,134217728,2147483648,34359738368, %T A013777 549755813888,8796093022208,140737488355328,2251799813685248, %U A013777 36028797018963968,576460752303423488,9223372036854775808,147573952589676412928,2361183241434822606848,37778931862957161709568 %N A013777 a(n) = 2^(4*n + 3). %H A013777 Vincenzo Librandi, <a href="/A013777/b013777.txt">Table of n, a(n) for n = 0..200</a> %H A013777 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>. %H A013777 <a href="/index/Di#divseq">Index to divisibility sequences</a>. %H A013777 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (16). %F A013777 From _Philippe Deléham_, Nov 23 2008: (Start) %F A013777 a(n) = 16*a(n-1); a(0)=8. %F A013777 G.f.: 8/(1-16*x). (End) %F A013777 From _Elmo R. Oliveira_, Feb 18 2025: (Start) %F A013777 E.g.f.: 8*exp(16*x). %F A013777 a(n) = A000079(A004767(n)). (End) %t A013777 2^(4*Range[0, 20] + 3) (* or *) %t A013777 NestList[16*# &, 8, 20] (* _Paolo Xausa_, Jul 21 2025 *) %o A013777 (Sage) [lucas_number1(4*n, 2, 0) for n in range(1, 17)] # _Zerinvary Lajos_, Oct 27 2009 %o A013777 (Magma) [2^(4*n+3): n in [0..20]]; // _Vincenzo Librandi_, Jun 27 2011 %o A013777 (PARI) a(n)=8<<(4*n) \\ _Charles R Greathouse IV_, Apr 08 2012 %Y A013777 Subsequence of A000079. %Y A013777 Cf. A004767. %K A013777 nonn,easy %O A013777 0,1 %A A013777 _N. J. A. Sloane_