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A020736 Pisot sequence L(5,8). 2
5, 8, 13, 22, 38, 66, 115, 201, 352, 617, 1082, 1898, 3330, 5843, 10253, 17992, 31573, 55406, 97230, 170626, 299427, 525457, 922112, 1618193, 2839730, 4983378, 8745218, 15346787, 26931733, 47261896, 82938845, 145547526, 255418102, 448227522, 786584467 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = 3*a(n-1) - 3*a(n-2) + 2*a(n-3) - a(n-4) (holds at least up to n = 1000 but is not known to hold in general).

MATHEMATICA

RecurrenceTable[{a[0] == 5, a[1] == 8, a[n] == Ceiling[a[n - 1]^2/a[n - 2]]}, a, {n, 0, 40}] (* Bruno Berselli, Feb 05 2016 *)

PROG

(MAGMA) Lxy:=[5, 8]; [n le 2 select Lxy[n] else Ceiling(Self(n-1)^2/Self(n-2)): n in [1..40]]; // Bruno Berselli, Feb 05 2016

(PARI) pisotL(nmax, a1, a2) = {

  a=vector(nmax); a[1]=a1; a[2]=a2;

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

  a

}

pisotL(50, 5, 8) \\ Colin Barker, Aug 07 2016

CROSSREFS

See A008776 for definitions of Pisot sequences.

Sequence in context: A020712 A182506 A111321 * A217185 A160421 A249719

Adjacent sequences:  A020733 A020734 A020735 * A020737 A020738 A020739

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified February 24 11:12 EST 2018. Contains 299603 sequences. (Running on oeis4.)