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 A369922 #24 Sep 05 2025 10:30:01
%S A369922 -1,1,51,197,487,969,1691,2701,4047,5777,7939,10581,13751,17497,21867,
%T A369922 26909,32671,39201,46547,54757,63879,73961,85051,97197,110447,124849,
%U A369922 140451,157301,175447,194937,215819,238141,261951,287297,314227,342789,373031,405001
%N A369922 a(n) = 8*n^3 - 6*n - 1.
%C A369922 This polynomial (evaluated over the rationals) arises in demonstrating the impossibility of trisecting an arbitrary angle by compass and straightedge.
%H A369922 Proofwiki, <a href="https://proofwiki.org/wiki/Trisecting_the_Angle_by_Compass_and_Straightedge_Construction_is_Impossible">Trisecting the Angle by Compass and Straightedge Construction is Impossible</a>.
%H A369922 Wikipedia, <a href="https://en.wikipedia.org/wiki/Angle_trisection">Angle trisection</a>.
%H A369922 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A369922 a(n) = 2*A144129(n) - 1.
%F A369922 From _Elmo R. Oliveira_, Sep 04 2025: (Start)
%F A369922 G.f.: (-1 + 5*x + 41*x^2 + 3*x^3)/(-1+x)^4.
%F A369922 E.g.f.: (-1 + 2*x + 24*x^2 + 8*x^3)*exp(x).
%F A369922 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
%t A369922 Table[8n^3-6n-1,{n,0,37}] (* _James C. McMahon_, Feb 05 2024 *)
%Y A369922 Cf. A144129.
%K A369922 sign,easy,changed
%O A369922 0,3
%A A369922 _Darío Clavijo_, Feb 05 2024