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 A147660 #7 Oct 02 2023 11:16:35
%S A147660 1,1,2,3,5,8,13,21,34,54,87,140,225,362,582,936,1505,2420,3892,6259,
%T A147660 10065,16186,26029,41858,67313,108248,174077,279938,450176,723941,
%U A147660 1164190,1872167,3010685,4841568,7785863,12520667,20134840,32379408,52070245,83735639,134657658,216546802,348235059
%N A147660 Expansion of 1/(1-x-x^2+x^9-x^11).
%H A147660 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1, 0, 0, 0, 0, 0, 0, -1, 0, 1).
%t A147660 f[x_] = -1 + x^2 - x^9 - x^10 + x^11;
%t A147660 g[x] = ExpandAll[x^11*f[1/x]];
%t A147660 a = Table[SeriesCoefficient[Series[1/g[x], {x, 0, 50}], n], {n, 0, 50}]
%K A147660 nonn,easy
%O A147660 0,3
%A A147660 _Roger L. Bagula_, Nov 09 2008