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 A089075 #17 Dec 24 2022 05:04:29
%S A089075 -1,1,-1,2,-2,4,-4,7,-7,12,-12,22,-21,39,-39,68,-70,119,-127,210,-229,
%T A089075 369,-413,649,-742,1143,-1334,2017,-2393,3561,-4289,6293,-7680,11129,
%U A089075 -13739,19696,-24559,34879,-43871,61801,-78324,109555,-139764,194291,-249295,344694,-444496,611723,-792285
%N A089075 A nonsense sequence.
%H A089075 G. C. Greubel, <a href="/A089075/b089075.txt">Table of n, a(n) for n = 1..1000</a>
%t A089075 (* k is a root of x^4 - x^3 - 1: *)
%t A089075 k=1.38027756909761411567330169182273187781662670155876302541177133121124957411;
%t A089075 q=k^2-k-1/k-1/k^2;
%t A089075 m0={{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 1, 1, q}};
%t A089075 m[n_]=MatrixPower[m0, n];
%t A089075 Table[Floor[Re[m[n][[4, 4]]]], {n, 1, 1000}]
%Y A089075 Cf. A089074, A089076, A089077.
%K A089075 sign,easy,less
%O A089075 1,4
%A A089075 _Roger L. Bagula_, Dec 04 2003
%E A089075 Edited by _G. C. Greubel_, Feb 19 2021