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A049416
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Largest number whose square has n digits.
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9
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3, 9, 31, 99, 316, 999, 3162, 9999, 31622, 99999, 316227, 999999, 3162277, 9999999, 31622776, 99999999, 316227766, 999999999, 3162277660, 9999999999, 31622776601, 99999999999, 316227766016, 999999999999, 3162277660168
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = ceiling(sqrt(10^n)) - 1.
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EXAMPLE
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31^2 = 961, but 32^2 = 1024, hence a(3) = 31.
a(4) = 99: 99^2 = 9801 has 4 digits, while 100^2 = 10000 has 5 digits.
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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nonn,base,easy,nice
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AUTHOR
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Ulrich Schimke (ulrschimke(AT)aol.com)
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EXTENSIONS
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More terms from Larry Reeves (larryr(AT)acm.org), May 16 2001
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STATUS
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approved
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