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A048592
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Pisot sequence L(9,10).
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1
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9, 10, 12, 15, 19, 25, 33, 44, 59, 80, 109, 149, 204, 280, 385, 530, 730, 1006, 1387, 1913, 2639, 3641, 5024, 6933, 9568, 13205, 18225, 25154, 34718, 47919, 66140, 91290, 126004, 173919, 240055, 331341, 457341, 631256, 871307, 1202644, 1659981, 2291233, 3162536
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) = 2*a(n-1) - a(n-2) + a(n-4) - a(n-5) (holds at least up to n = 1000 but is not known to hold in general).
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MATHEMATICA
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RecurrenceTable[{a[0] == 9, a[1] == 10, a[n] == Ceiling[a[n - 1]^2/a[n - 2]]}, a, {n, 0, 50}] (* Bruno Berselli, Feb 04 2016 *)
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PROG
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(Magma) Lxy:=[9, 10]; [n le 2 select Lxy[n] else Ceiling(Self(n-1)^2/Self(n-2)): n in [1..50]]; // Bruno Berselli, Feb 04 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
}
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CROSSREFS
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See A008776 for definitions of Pisot sequences.
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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