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A063721
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Number of proper divisors of n is a square and sets a new record for such squares.
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1
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1, 2, 16, 48, 6480, 331776, 26542080, 207360000, 174142586880, 5476584960000, 8352895346933760000, 190741334440500264960000, 40745645800296001044480000, 11921333402531266560000000000000000
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..14.
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PROG
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(PARI) a=-1; for(n=1, 10^7, x=numdiv(n)-1; if(issquare(x), b=x; if(b>a, a=b; print(n))))
(PARI) {a063721(m)=local(r, n, x); r=-1; for(n=1, m, x=numdiv(n)-1; if(issquare(x) && x>r, r=x; print1(n, ", "))) }
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CROSSREFS
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Cf. A032741.
Sequence in context: A162442 A159010 A223219 * A232209 A012180 A058376
Adjacent sequences: A063718 A063719 A063720 * A063722 A063723 A063724
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KEYWORD
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nonn
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AUTHOR
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Jason Earls, Aug 22 2001
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EXTENSIONS
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More terms from Don Reble, May 12 2002
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STATUS
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approved
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