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A171237 a(0)=2, a(1)=3, a(n) = 3 + a(n-1) + a(n-2) for n >= 2. 1

%I #18 Mar 19 2020 18:27:14

%S 2,3,8,14,25,42,70,115,188,306,497,806,1306,2115,3424,5542,8969,14514,

%T 23486,38003,61492,99498,160993,260494,421490,681987,1103480,1785470,

%U 2888953,4674426,7563382,12237811,19801196,32039010,51840209,83879222

%N a(0)=2, a(1)=3, a(n) = 3 + a(n-1) + a(n-2) for n >= 2.

%C a(n) gives the time complexity of a recursive Fibonacci algorithm.

%H Harvey P. Dale, <a href="/A171237/b171237.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,-1).

%F a(0)=2, a(1)=3, a(n) = 3 + a(n-1) + a(n-2) n >= 2.

%F From _R. J. Mathar_, Dec 06 2009: (Start)

%F a(n) = 2*a(n-1) - a(n-3) = A022095(n+1) - 3.

%F G.f.: (2-x+2*x^2)/((x-1)*(x^2+x-1)). (End)

%t LinearRecurrence[{2,0,-1},{2,3,8},50] (* _Harvey P. Dale_, Mar 19 2020 *)

%K nonn,easy

%O 0,1

%A Manfred Jackel (jkl(AT)uni-koblenz.de), Dec 05 2009

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Last modified April 12 06:13 EDT 2024. Contains 371623 sequences. (Running on oeis4.)