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A019480
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Define the sequence S(a(0),a(1)) by a(n+2) is the least integer such that a(n+2)/a(n+1) > a(n+1)/a(n) for n >= 0. This is S(4,12) (agrees with A019481 for n <= 19 only).
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3
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4, 12, 37, 115, 358, 1115, 3473, 10818, 33697, 104963, 326950, 1018419, 3172281, 9881362, 30779529, 95875387, 298642966, 930245227, 2897627873, 9025842914, 28114666162, 87574585658, 272786737320, 849705465331, 2646753962113, 8244393877392, 25680524664755
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OFFSET
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0,1
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LINKS
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MAPLE
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a:= proc(n) option remember;
`if`(n<2, [4, 12][n+1], floor(a(n-1)^2/a(n-2))+1)
end:
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MATHEMATICA
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S[a_, b_, n_] := Block[{s = {a, b}, k}, Do[k = Last@ s + 1; While[k/s[[i - 1]] <= s[[i - 1]]/s[[i - 2]], k++]; AppendTo[s, k], {i, 3, n}]; s]; S[4, 12, 14] (* Michael De Vlieger, Feb 15 2016 *)
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PROG
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(PARI) S(a0, a1, maxn) = a=vector(maxn); a[1]=a0; a[2]=a1; for(n=3, maxn, a[n]=a[n-1]^2\a[n-2]+1); a
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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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