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 A369327 #9 Jan 22 2024 00:03:13
%S A369327 1,1,4,24,149,923,5784,36708,235156,1516864,9838018,64093998,
%T A369327 419137378,2749637566,18087479624,119263349200,788015054253,
%U A369327 5216212564723,34584497597602,229635524379026,1526740206967913,10162620233598959,67719554546286284,451699650863065424
%N A369327 a(n) is the number of words of length n over the alphabet [n] and sortable by a (2,1)-pop stack of depth 2.
%H A369327 Toufik Mansour, Howard Skogman, and Rebecca Smith, <a href="https://arxiv.org/abs/2401.06662">Sorting inversion sequences</a>, arXiv:2401.06662 [math.CO], 2024. See Theorem 3.25 at page 13.
%F A369327 a(n) = A369326(n, n).
%t A369327 A369326[n_,k_]:=SeriesCoefficient[((1-x)(1-2x)-((1-x)(1-2x)+x^2)y)/((1-x)(1-2x)-(1-x)(2-3x)y+(1-2x)y^2),{x,0,n},{y,0,k}]; a[n_]:=A369326[n,n]; Array[a,24,0]
%Y A369327 Main diagonal of A369326.
%Y A369327 Cf. A369325.
%K A369327 nonn
%O A369327 0,3
%A A369327 _Stefano Spezia_, Jan 20 2024