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Expansion of x + 1/(-x - 1/(-x - 1/(-x + 1))).
1

%I #16 Jun 12 2024 11:41:13

%S 1,4,6,14,31,70,157,353,793,1782,4004,8997,20216,45425,102069,229347,

%T 515338,1157954,2601899,5846414,13136773,29518061,66326481,149034250,

%U 334876920,752461609,1690765888,3799116465,8536537209,19181424995,43100270734,96845429254

%N Expansion of x + 1/(-x - 1/(-x - 1/(-x + 1))).

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,1,-1).

%F a(n) = [x^n] (x^4 - x^3 - 3*x^2 + 2*x + 1) / (x^3 - x^2 - 2*x + 1).

%t CoefficientList[Series[x + 1/(-x - 1/(-x - 1/(-x + 1))), {x, 0, 31}], x] (* _Michael De Vlieger_, Jun 10 2024 *)

%Y Essentially the same as A006356.

%K nonn,easy

%O 0,2

%A _Peter Luschny_, Jun 10 2024