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 A099211 #9 Mar 19 2025 21:13:53 %S A099211 1,-2,4,-4,0,16,-48,96,-128,64,256,-1024,2304,-3584,3072,3072,-20480, %T A099211 53248,-94208,106496,0,-376832,1179648,-2359296,3211264,-1703936, %U A099211 -6029312,24903680,-56623104,89128960,-78643200,-69206016,494927872,-1304428544,2332033024,-2684354560 %N A099211 a(n) = -2*a(n-1) + 4*a(n-3), with a(0) = 1, a(1) = -2, a(2) = 4. %H A099211 Andrew Howroyd, <a href="/A099211/b099211.txt">Table of n, a(n) for n = 0..1000</a> %H A099211 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (-2,0,4). %F A099211 G.f.: 1/(1 + 2*x - 4*x^3). %F A099211 a(n) = A099212(n+4)/4. %Y A099211 Cf. A099212. %K A099211 easy,sign %O A099211 0,2 %A A099211 _Paul Barry_, Oct 06 2004 %E A099211 a(32) onwards from _Andrew Howroyd_, Mar 19 2025