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 A122605 #26 Sep 19 2017 03:56:41
%S A122605 1,0,0,0,0,0,0,-1,-1,-7,-8,-35,-44,-154,-208,-637,-910,-2548,-3808,
%T A122605 -9996,-15504,-38760,-62015,-149225,-245135,-572010,-961125,-2186886,
%U A122605 -3746886,-8348172,-14547183,-31842580,-56309764,-121415344,-217478888,-462925232,-838520240,-1765205473,-3228800413
%N A122605 Expansion of -x*(2*x - 1)*(2*x^2 - 1)*(x^3 + 2*x^2 - x - 1)/((x - 1)*(x^2 + x - 1)*(x^4 - 4*x^3 - 4*x^2 + x + 1)).
%H A122605 Peter Steinbach, <a href="http://www.jstor.org/stable/2691048">Golden fields: a case for the heptagon</a>, Math. Mag. Vol. 70, No. 1, Feb. 1997, 22-31.
%H A122605 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,6,-5,-10,6,4,-1).
%F A122605 a(0)=1, a(1)=a(2)=a(3)=a(4)=a(5)=a(6)=0; for n>6, a(n) = a(n-1) + 6*a(n-2) - 5*a(n-3) - 10*a(n-4) + 6*a(n-5) + 4*a(n-6) - a(n-7). - _Harvey P. Dale_, May 02 2011
%F A122605 G.f.: -x*(2*x-1)*(2*x^2-1)*(x^3+2*x^2-x-1)/((x-1)*(x^2+x-1)*(x^4-4*x^3-4*x^2+x+1)). - _Colin Barker_, Nov 08 2012
%t A122605 LinearRecurrence[{1,6,-5,-10,6,4,-1},{1,0,0,0,0,0,0},60] (* _Harvey P. Dale_, May 02 2011 *)
%Y A122605 Cf. A066170.
%K A122605 sign,easy
%O A122605 1,10
%A A122605 _Roger L. Bagula_ and _Gary W. Adamson_, Sep 20 2006
%E A122605 Edited by _N. J. A. Sloane_, Feb 11 2007
%E A122605 Definition changed using Barker's g.f. by _Bruno Berselli_, Sep 19 2017