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 A200739 #23 Apr 28 2025 15:19:32
%S A200739 1,0,0,1,5,24,116,561,2713,13120,63448,306833,1483837,7175800,
%T A200739 34701996,167818017,811563889,3924703424,18979771248,91785716705,
%U A200739 443873515701,2146561633048,10380720366244,50200913713873,242770409836169,1174031855833216,5677589783043784
%N A200739 Expansion of (-x^2+5*x-1)/(x^3-x^2+5*x-1).
%C A200739 _Peter A. Lawrence_ (see links) has posted a challenge to find a 3x3 integer matrix with "smallish" elements whose powers generate a sequence that is not in the OEIS. This sequence is one of the solutions found.
%H A200739 Alois P. Heinz, <a href="/A200739/b200739.txt">Table of n, a(n) for n = 0..450</a>
%H A200739 Peter Lawrence et al., <a href="https://web.archive.org/web/20220127112002/http://list.seqfan.eu/pipermail/seqfan/2011-November/008535.html">sequence challenge</a> and follow-up messages on the SeqFan list, Nov 21 2011
%H A200739 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-1,1)
%F A200739 G.f.: (-x^2+5*x-1)/(x^3-x^2+5*x-1).
%F A200739 Term (1,1) in the 3x3 matrix [0,1,0; 0,0,1; 1,-1,5]^n.
%p A200739 a:= n-> (<<0|1|0>, <0|0|1>, <1|-1|5>>^n)[1, 1]:
%p A200739 seq(a(n), n=0..30);
%t A200739 CoefficientList[Series[(-x^2 + 5 x - 1)/(x^3 - x^2 + 5 x - 1), {x, 0, 30}], x] (* or *) LinearRecurrence[{5,-1,1},{1,0,0},30] (* _Harvey P. Dale_, Nov 26 2017 *)
%Y A200739 Cf. A200676.
%K A200739 nonn,easy
%O A200739 0,5
%A A200739 _Alois P. Heinz_, Nov 21 2011