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 A099166 #10 Dec 31 2023 16:17:54
%S A099166 1,3,9,22,51,113,244,517,1081,2238,4599,9397,19116,38753,78349,158062,
%T A099166 318331,640233,1286244,2581837,5178801,10382078,20803759,41671597,
%U A099166 83446876,167061513,334394469,669228142,1339166931,2679483713
%N A099166 G.f.: (1+x^2)/((1-2x)(1-x-x^2)); a(n)=3a(n-1)-a(n-2)-2a(n-3); a(n)=5*2^n-L(n+3); a(n)=sum{k=0..n, (L(k)-0^k)2^(n-k)}.
%C A099166 A Lucas convolution.
%H A099166 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-1,-2).
%Y A099166 Cf. A000032, A099167.
%K A099166 easy,nonn
%O A099166 0,2
%A A099166 _Paul Barry_, Oct 01 2004