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A153885 a(n) = ((8 + sqrt(5))^n - (8 - sqrt(5))^n)/(2*sqrt(5)). 1

%I #14 Sep 08 2022 08:45:40

%S 1,16,197,2208,23705,249008,2585533,26677056,274286449,2814636880,

%T 28851289589,295557057504,3026686834313,30989122956272,

%U 317251444075885,3247664850794112,33244802412228577,340304612398804624,3483430456059387941,35656915165420734240

%N a(n) = ((8 + sqrt(5))^n - (8 - sqrt(5))^n)/(2*sqrt(5)).

%C Sixth binomial transform of A048879.

%C lim_{n -> infinity} a(n)/a(n-1) = 8 + sqrt(5) = 10.236067977499789696....

%H G. C. Greubel, <a href="/A153885/b153885.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (16, -59).

%F From _Philippe Deléham_, Jan 03 2009: (Start)

%F a(n) = 16*a(n-1) - 59*a(n-2) for n>1, with a(0)=0, a(1)=1.

%F G.f.: x/(1 - 16*x + 59*x^2). (End)

%t Join[{a=1,b=16},Table[c=16*b-59*a;a=b;b=c,{n,40}]] (* _Vladimir Joseph Stephan Orlovsky_, Feb 08 2011*)

%t LinearRecurrence[{16, -59}, {1, 16}, 25] (* or *) Table[((8 + sqrt(5))^n - (8 - sqrt(5))^n)/(2*sqrt(5)) , {n,1,25}] (* _G. C. Greubel_, Aug 31 2016 *)

%o (Magma) Z<x>:= PolynomialRing(Integers()); N<r>:=NumberField(x^2-5); S:=[ ((8+r)^n-(8-r)^n)/(2*r): n in [1..18] ]; [ Integers()!S[j]: j in [1..#S] ]; # _Klaus Brockhaus_, Jan 04 2009

%o (Magma) I:=[1,16]; [n le 2 select I[n] else 16*Self(n-1)-59*Self(n-2): n in [1..30]]; // _Vincenzo Librandi_, Sep 01 2016

%Y Cf. A002163 (decimal expansion of sqrt(5)), A048879.

%K nonn

%O 1,2

%A Al Hakanson (hawkuu(AT)gmail.com), Jan 03 2009

%E Extended beyond a(7) by _Klaus Brockhaus_, Jan 04 2009

%E Edited by _Klaus Brockhaus_, Oct 11 2009

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Last modified April 24 17:02 EDT 2024. Contains 371962 sequences. (Running on oeis4.)