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 A171559 #6 Jun 29 2023 12:59:50 %S A171559 3,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536, %T A171559 131072,262144,524288,1048576,2097152,4194304,8388608,16777216, %U A171559 33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592 %N A171559 Powers of 2 (cf. A000079) with 1 replaced by 3. %C A171559 First differences of A171449. %H A171559 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (2). %F A171559 a(n+1)-a(n) = A171449(n). %F A171559 a(n) + A171449(n) = A000079(n+1) = 2*A000079(n). %F A171559 G.f.: (3-4*x)/(1-2*x). %K A171559 nonn,less %O A171559 0,1 %A A171559 _Paul Curtz_, Dec 11 2009 %E A171559 Edited by _R. J. Mathar_ and _N. J. A. Sloane_, Dec 15 2009