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%I #14 Sep 08 2022 08:44:44
%S 4,11,30,81,218,586,1575,4233,11377,30578,82185,220890,593690,1595671,
%T 4288713,11526849,30980914,83267945,223800714,601513098,1616697287,
%U 4345225609,11678738961,31389151218,84365171401
%N a(n) = 3*a(n-1) - 3*a(n-3) + 2*a(n-4), with a(0)=4, a(1)=11.
%D R. K. Guy, personal communication.
%H G. C. Greubel, <a href="/A019496/b019496.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3, 0, -3, 2).
%F G.f.: (4-x-3*x^2+3*x^3)/(1-3*x+3*x^3-2*x^4). - _Harvey P. Dale_, Oct 25 2011
%t LinearRecurrence[{3,0,-3,2},{4,11,30,81},30] (* _Harvey P. Dale_, Oct 25 2011 *)
%o (PARI) my(x='x+O('x^30)); Vec((4-x-3*x^2+3*x^3)/(1-3*x+3*x^3-2*x^4)) \\ _G. C. Greubel_, Mar 24 2019
%o (Magma) I:=[4,11,30,81]; [n le 4 select I[n] else 3*Self(n-1)- 3*Self(n-3) +2*Self(n-4): n in [1..30]]; // _G. C. Greubel_, Mar 24 2019
%o (Sage) ((4-x-3*x^2+3*x^3)/(1-3*x+3*x^3-2*x^4)).series(x, 30).coefficients(x, sparse=False) # _G. C. Greubel_, Mar 24 2019
%K nonn
%O 0,1
%A _N. J. A. Sloane_
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