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 A372874 #8 May 17 2024 01:41:34
%S A372874 1,4,14,50,179,632,2192,7478,25157,83660,275570,900506,2922935,
%T A372874 9433088,30292148,96855134,308501513,979312916,3099363926,9782367362,
%U A372874 30799928891,96758267144,303350242904,949277053190,2965510133069,9249567319772,28807812721082,89600770448618
%N A372874 a(n) is the total number of runs of descents over all flattened Catalan words of length n.
%H A372874 Jean-Luc Baril, Pamela E. Harris, and José L. Ramírez, <a href="https://arxiv.org/abs/2405.05357">Flattened Catalan Words</a>, arXiv:2405.05357 [math.CO], 2024. See pp. 11-12.
%H A372874 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (8,-22,24,-9).
%F A372874 From Baril et al.: (Start)
%F A372874 G.f.: x*(1 - 4*x + 4*x^2 + 2*x^3)/((1 - x)^2*(1 - 3*x)^2).
%F A372874 a(n) = (27*n - 9 + (5*n + 1)*3^n)/36. (End)
%F A372874 E.g.f.: (8 + 9*exp(x)*(3*x - 1) + exp(3*x)*(15*x+1))/36.
%t A372874 LinearRecurrence[{8,-22,24,-9},{1,4,14,50},28]
%Y A372874 Cf. A372873.
%K A372874 nonn,easy
%O A372874 1,2
%A A372874 _Stefano Spezia_, May 15 2024