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Pisot sequence T(7,9).
4

%I #17 Jul 08 2023 16:17:30

%S 7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,

%T 53,55,57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93,95,97,

%U 99,101,103,105,107,109,111,113,115,117,119,121,123,125,127,129,131,133,135,137,139

%N Pisot sequence T(7,9).

%H Colin Barker, <a href="/A020742/b020742.txt">Table of n, a(n) for n = 0..1000</a>

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2, -1).

%F a(n) = 2n+7. a(n) = 2a(n-1) - a(n-2).

%t T[x_, y_, z_] := Block[{a}, a[0] = x; a[1] = y; a[n_] := a[n] = Floor[a[n - 1]^2/a[n - 2]]; Table[a[n], {n, 0, z}]]; T[7, 9, 66] (* _Michael De Vlieger_, Aug 08 2016 *)

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

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

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

%o a

%o }

%o pisotT(50, 7, 9) \\ _Colin Barker_, Aug 08 2016

%Y Subsequence of A005408, A020735. See A008776 for definitions of Pisot sequences.

%K nonn,easy

%O 0,1

%A _David W. Wilson_