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 A329723 #36 Oct 21 2023 03:35:00
%S A329723 1,1,2,1,3,4,7,11,18,29,47,76,123,199,322,521,843,1364,2207,3571,5778,
%T A329723 9349,15127,24476,39603,64079,103682,167761,271443,439204,710647,
%U A329723 1149851,1860498,3010349,4870847,7881196,12752043,20633239,33385282,54018521,87403803,141422324,228826127
%N A329723 Coefficients of expansion of (1-2x^3)/(1-x-x^2) in powers of x.
%C A329723 Two terms 1, 1 followed by the Lucas sequence (A000032), i.e., A000032(n) = a(n+2). The run length transform is given by Sum_{k=0..n} ((binomial(n+2k,2n-k)*binomial(n,k)) mod 2) (A329722).
%H A329723 Chai Wah Wu, <a href="/A329723/b329723.txt">Table of n, a(n) for n = 0..4786</a>
%H A329723 Narad Rampersad and Max Wiebe, <a href="https://arxiv.org/abs/2309.04012">Sums of products of binomial coefficients mod 2 and 2-regular sequences</a>, arXiv:2309.04012 [math.NT], 2023.
%H A329723 Chai Wah Wu, <a href="https://arxiv.org/abs/1610.06166">Sums of products of binomial coefficients mod 2 and run length transforms of sequences</a>, arXiv:1610.06166 [math.CO], 2016.
%H A329723 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (1,1).
%F A329723 a(n) = A000032(n-2) for n > 1.
%F A329723 a(n) = a(n-1) + a(n-2) for n > 3. - _Chai Wah Wu_, Feb 04 2022
%t A329723 CoefficientList[Series[(1 - 2 x^3)/(1 - x - x^2), {x, 0, 42}], x] (* _Michael De Vlieger_, Feb 04 2022 *)
%o A329723 (Python)
%o A329723 from sympy import lucas
%o A329723 def A329723(n): return 1 if n <= 1 else lucas(n-2) # _Chai Wah Wu_, Feb 04 2022
%Y A329723 Cf. A000032, A329722.
%K A329723 nonn,easy
%O A329723 0,3
%A A329723 _Chai Wah Wu_, Nov 19 2019