A065886 - OEIS

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A065886

Smallest square divisible by n!.

1, 1, 4, 36, 144, 3600, 3600, 176400, 2822400, 25401600, 25401600, 3073593600, 110649369600, 18699743462400, 74798973849600, 1869974346240000, 29919589539840000, 8646761377013760000, 77820852393123840000 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,3`
	LINKS	`Table of n, a(n) for n=0..18.`
	FORMULA	`a(n) = A053143(A000142(n)) = A065887(n)^2 = A000142(n)*A055204(n) = A001044(n)/A055071(n)`
	EXAMPLE	`a(10) = 25401600 since 10! = 3628800 and the smallest square divisible by this is 25401600 = 3628800*7 = 5040^2`
	MATHEMATICA	`ssd[n_]:=Module[{nf=n!, k=1}, While[!IntegerQ[Sqrt[knf]], k++]; knf]; Array[ssd, 20, 0] (* From Harvey P. Dale, Apr 29 2012 *)`
	CROSSREFS	`Sequence in context: A007407 A051418 A069046 * A069053 A193282 A192217` `Adjacent sequences: A065883 A065884 A065885 * A065887 A065888 A065889`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley, Nov 27 2001`
	STATUS	`approved`

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Last modified May 18 08:58 EDT 2013. Contains 225419 sequences.