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A087675
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Consider recurrence b(0) = (2n+1)/2, b(n) = b(0)*floor(b(n-1)); sequence gives first integer reached.
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3
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5, 35, 18, 814, 39, 390, 68, 72827, 105, 1449, 150, 31887, 203, 3596, 264, 27852510, 333, 7215, 410, 208464, 495, 12690, 588, 10561998, 689, 20405, 798, 744049, 915, 30744, 1040, 46620858503, 1173, 44091, 1314, 1950450, 1463, 60830, 1620, 121575329, 1785
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OFFSET
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2,1
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LINKS
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J. C. Lagarias and N. J. A. Sloane, Approximate squaring (pdf, ps), Experimental Math., 13 (2004), 113-128.
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FORMULA
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The even-indexed terms are given by A007742.
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MAPLE
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f:= proc(n)
local b0, b;
b0:= (2*n+1)/2;
b:= b0;
do
b:= b0*floor(b);
if b::integer then return b fi
od
end proc:
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MATHEMATICA
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f[n_] := Module[{b0, b}, b0 = (2n+1)/2; b = b0; While[True, b = b0*Floor[b]; If[IntegerQ[b], Return[b]]]];
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CROSSREFS
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A001511 gives number of steps to reach an integer.
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KEYWORD
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AUTHOR
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N. J. A. Sloane, following a suggestion of Bela Bajnok (bbajnok(AT)gettysburg.edu), Sep 27 2003
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EXTENSIONS
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STATUS
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approved
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