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 A122767 #22 Jan 01 2023 02:57:40
%S A122767 0,2,12,312,2712,50112,532512,8394912,99237312,1443059712,18048362112,
%T A122767 251686144512,3243002406912,44245843149312,579129504371712,
%U A122767 7811377482074112,103090052472256512,1382166761370918912
%N A122767 Expansion of 2*x/(1-6*x-120*x^2+300*x^3).
%H A122767 G. C. Greubel, <a href="/A122767/b122767.txt">Table of n, a(n) for n = 0..875</a>
%H A122767 P. Steinbach, <a href="http://www.jstor.org/stable/2691048">Golden fields: a case for the heptagon</a>, Math. Mag. 70 (1997), no. 1, 22-31.
%H A122767 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6,120,-300).
%t A122767 CoefficientList[Series[2x/(1-6x-120x^2+300x^3),{x,0,20}],x] (* or *) LinearRecurrence[{6,120,-300},{0,2,12},20] (* _Harvey P. Dale_, Oct 16 2016 *)
%o A122767 (PARI) Vec(2*x/(1-6*x-120*x^2+300*x^3)+O(x^99)) \\ _Charles R Greathouse IV_, Sep 27 2012
%o A122767 (Magma) R<x>:=PowerSeriesRing(Integers(), 30); [0] cat Coefficients(R!( 2*x/(1-6*x-120*x^2+300*x^3) )); // _G. C. Greubel_, Dec 31 2022
%o A122767 (SageMath)
%o A122767 def A122767_list(prec):
%o A122767 P.<x> = PowerSeriesRing(ZZ, prec)
%o A122767 return P( 2*x/(1-6*x-120*x^2+300*x^3) ).list()
%o A122767 A122767_list(30) # _G. C. Greubel_, Dec 31 2022
%Y A122767 Cf. A078008, A122601.
%K A122767 nonn,easy,less
%O A122767 0,2
%A A122767 _Roger L. Bagula_ and _Gary W. Adamson_, Sep 22 2006