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 A176288 #11 Sep 08 2022 08:45:52
%S A176288 1,3,15,55,131,163,-169,-1521,-4437,-7429,-2945,26471,101587,207699,
%T A176288 201639,-306497,-1907461,-4718165,-6464305,547863,30463779,93816323,
%U A176288 161591287,97035119,-400669877,-1676486565,-3504149217,-3693262649
%N A176288 Hankel transform of A176287.
%H A176288 G. C. Greubel, <a href="/A176288/b176288.txt">Table of n, a(n) for n = 0..1000</a>
%H A176288 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (6,-17,24,-16).
%F A176288 G.f.: (1-3*x+14*x^2-8*x^3)/(1-3*x+4*x^2)^2.
%F A176288 a(n) = 2^n*( (2n+7)*sin(2n*atan(1/sqrt(7)))/sqrt(7) - (2*n-1)*cos(2n*atan(1/sqrt(7)))).
%p A176288 seq(coeff(series((1-3*x+14*x^2-8*x^3)/(1-3*x+4*x^2)^2, x, n+1), x, n), n = 0..30); # _G. C. Greubel_, Nov 25 2019
%t A176288 LinearRecurrence[{6,-17,24,-16},{1,3,15,55},30] (* _Harvey P. Dale_, Jun 12 2017 *)
%o A176288 (PARI) my(x='x+O('x^30)); Vec((1-3*x+14*x^2-8*x^3)/(1-3*x+4*x^2)^2) \\ _G. C. Greubel_, Nov 25 2019
%o A176288 (Magma) R<x>:=PowerSeriesRing(Integers(), 30); Coefficients(R!( (1-3*x+14*x^2-8*x^3)/(1-3*x+4*x^2)^2 )); // _G. C. Greubel_, Nov 25 2019
%o A176288 (Sage)
%o A176288 def A176288_list(prec):
%o A176288 P.<x> = PowerSeriesRing(ZZ, prec)
%o A176288 return P( (1-3*x+14*x^2-8*x^3)/(1-3*x+4*x^2)^2 ).list()
%o A176288 A176288_list(30) # _G. C. Greubel_, Nov 25 2019
%o A176288 (GAP) a:=[1,3,15,55];; for n in [5..30] do a[n]:=6*a[n-1]-17*a[n-2]+24*a[n-3] -16*a[n-4]; od; a; # _G. C. Greubel_, Nov 25 2019
%K A176288 easy,sign
%O A176288 0,2
%A A176288 _Paul Barry_, Apr 14 2010