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A055772
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Square root of largest square dividing n!.
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17
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1, 1, 1, 2, 2, 12, 12, 24, 72, 720, 720, 1440, 1440, 10080, 30240, 120960, 120960, 725760, 725760, 7257600, 7257600, 79833600, 79833600, 958003200, 4790016000, 62270208000, 186810624000, 2615348736000, 2615348736000, 15692092416000
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OFFSET
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1,4
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LINKS
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FORMULA
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EXAMPLE
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For n=6, 6!=720=144*5 so a(6)=sqrt(144)=12.
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MAPLE
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a:= proc(n)
local r, F, t;
r:= n!;
F:= ifactors(r)[2];
mul(t[1]^floor(t[2]/2), t=F)
end proc:
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MATHEMATICA
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Table[Last[Select[Sqrt[#]&/@Divisors[n!], IntegerQ]], {n, 30}] (* Harvey P. Dale, Oct 08 2012 *)
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PROG
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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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