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A208212
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a(n) = (a(n-1)^2*a(n-2)^5+1)/a(n-3) with a(0)=a(1)=a(2)=1.
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2
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OFFSET
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0,4
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COMMENTS
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This is the case a=5, b=2, y(0)=y(1)=y(2)=1 of the recurrence shown in the Example 3.2 of "The Laurent phenomenon" (see Link lines, p. 10).
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LINKS
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Sergey Fomin and Andrei Zelevinsky, The Laurent phenomenon, arXiv:math/0104241v1 [math.CO] (2001); Advances in Applied Mathematics 28 (2002), 119-144.
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FORMULA
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a(n) ~ c1^(d1^n) * c2^(d2^n) * c3^(d3^n), where
d1 = -1.575773472651936072015953246349296378313356749177416595434978648425...
d2 = 0.1872837251102239188569922313039458439968721185362219238420888422761...
d3 = 3.3884897475417121531589610150453505343164846306411946715928898061494...
are the roots of the equation d^3 + 1 = 2*d^2 + 5*d and
c1 = 0.9607631794694254165284953988161129828633931861764073755339129251426...
c2 = 0.1625672201779811599302887070429221376610589038410298300467412998556...
c3 = 1.0141969317515019907302101637404918873873074910913934972790303073225...
(End)
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MAPLE
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a:=proc(n) if n<3 then return 1: fi: return (a(n-1)^2*a(n-2)^5+1)/a(n-3): end: seq(a(i), i=0..10);
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MATHEMATICA
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a[n_] := a[n] = If[n <= 2, 1, (a[n - 1]^2*a[n - 2]^5 + 1)/a[n - 3]];
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CROSSREFS
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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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