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 A053566 #19 Sep 08 2022 08:45:00
%S A053566 -2,-1,12,81,378,1539,5832,21141,74358,255879,866052,2893401,9565938,
%T A053566 31355019,102036672,330024861,1061819118,3400690959,10847773692,
%U A053566 34480423521,109252577898,345191655699
%N A053566 Expansion of (11*x-2)/(1-3*x)^2.
%D A053566 A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 189, 194-196.
%H A053566 Harvey P. Dale, <a href="/A053566/b053566.txt">Table of n, a(n) for n = 0..1000</a>
%H A053566 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-9).
%F A053566 a(n) = 3^(n-1)*(5*n-6).
%F A053566 a(n) = 6*a(n-1) - 9*a(n-2), with a(0) = -2, a(1) = -1.
%F A053566 E.g.f.: (5*x - 2)*exp(3*x). - _G. C. Greubel_, May 16 2019
%t A053566 LinearRecurrence[{6,-9},{-2,-1},30] (* _Harvey P. Dale_, Jun 26 2012 *)
%o A053566 (PARI) Vec((11*x-2)/(1-3*x)^2 + O(x^30)) \\ _Michel Marcus_, Dec 03 2014
%o A053566 (Magma) [3^(n-1)*(5*n-6) : n in [0..30]]; // _G. C. Greubel_, May 16 2019
%o A053566 (Sage) [3^(n-1)*(5*n-6) for n in (0..30)] # _G. C. Greubel_, May 16 2019
%o A053566 (GAP) List([0..30], n-> 3^(n-1)*(5*n-6)) # _G. C. Greubel_, May 16 2019
%Y A053566 Cf. A023444.
%K A053566 easy,sign
%O A053566 0,1
%A A053566 _Barry E. Williams_, Jan 17 2000