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Pisot sequence P(6,9).
2

%I #16 Aug 08 2016 17:18:26

%S 6,9,13,19,28,41,60,88,129,189,277,406,595,872,1278,1873,2745,4023,

%T 5896,8641,12664,18560,27201,39865,58425,85626,125491,183916,269542,

%U 395033,578949,848491,1243524,1822473,2670964,3914488,5736961,8407925,12322413,18059374

%N Pisot sequence P(6,9).

%H Colin Barker, <a href="/A048626/b048626.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 (1,0,1).

%F a(n) = a(n-1) + a(n-3) (Checked up to n = 1000)

%F a(n) = A048625(n+1). - _R. J. Mathar_, Oct 15 2008

%t LinearRecurrence[{1, 0, 1}, {6, 9, 13}, 42] (* _Robert G. Wilson v_, Jul 12 2014 *)

%o (PARI) pisotP(nmax, a1, a2) = {

%o a=vector(nmax); a[1]=a1; a[2]=a2;

%o for(n=3, nmax, a[n] = ceil(a[n-1]^2/a[n-2]-1/2));

%o a

%o }

%o pisotP(50, 6, 9) \\ _Colin Barker_, Aug 08 2016

%Y Subsequence of A048625, A000930. See A008776 for definitions of Pisot sequences.

%Y Cf. A020721.

%K nonn

%O 0,1

%A _David W. Wilson_