

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
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OFFSET

0,1


LINKS

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


FORMULA

a(n) = 3*a(n1)  3*a(n2) + 2*a(n3)  a(n4) (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(n1)^2/Self(n2)): 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[n1]^2/a[n2]));
a
}
pisotL(50, 5, 8) \\ Colin Barker, Aug 07 2016


CROSSREFS

See A008776 for definitions of Pisot sequences.
Sequence in context: A314468 A111321 A306943 * A314469 A217185 A160421
Adjacent sequences: A020733 A020734 A020735 * A020737 A020738 A020739


KEYWORD

nonn


AUTHOR

David W. Wilson


STATUS

approved



