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A089245
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Integer part of square root of the reciprocal of a number multiplied by 10 to the power of the integer part of the square root of the number.
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0
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10, 7, 5, 50, 44, 40, 37, 35, 333, 316, 301, 288, 277, 267, 258, 2500, 2425, 2357, 2294, 2236, 2182, 2132, 2085, 2041, 20000, 19611, 19245, 18898, 18569, 18257, 17960, 17677, 17407, 17149, 16903, 166666, 164398, 162221, 160128, 158113, 156173
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OFFSET
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1,1
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COMMENTS
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The sum of the reciprocals = 0.595091701724608076103001212.. Converges rapidly.
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LINKS
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FORMULA
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floor( sqrt(1/x)*10^(floor(sqrt(x))) )
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MATHEMATICA
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Table[Floor[Sqrt[1/x] 10^Floor[Sqrt[x]]], {x, 50}] (* Harvey P. Dale, Feb 01 2022 *)
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PROG
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(PARI) rootrecip(n) = { sr=0; for(x=1, n, r =sqrt(x); ip=floor(r); fp=r-ip; y=floor((1/r)*10^ip); print1(y", "); sr = sr + 1.0/y; ); print(); print(sr) }
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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