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A292441
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Largest m such that m^2 divides A000984(n).
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2
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1, 1, 1, 2, 1, 6, 2, 2, 3, 2, 2, 2, 2, 10, 30, 12, 3, 6, 10, 10, 6, 2, 2, 60, 30, 42, 42, 28, 2, 4, 4, 4, 21, 14, 14, 6, 2, 2, 10, 140, 14, 126, 6, 60, 90, 12, 84, 84, 210, 30, 18, 12, 6, 36, 4, 4, 6, 4, 4, 12, 12, 132, 132, 440, 55, 330, 10, 10, 90, 30, 30, 180
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OFFSET
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0,4
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COMMENTS
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a(n) is the product of p^floor(m(n,p)/2) over primes p<n, where m(n,p) is the number of carries when adding n to itself in base p. - Robert Israel, Sep 17 2017
Granville and Ramaré show that A006530(a(n)) > sqrt(n/5) if n >= 2082.
In particular a(n) -> infinity as n -> infinity. - Robert Israel, Sep 18 2017
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LINKS
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FORMULA
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a(n) > 1 for n > 4.
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EXAMPLE
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binomial(10,5)/7 = 252/7 = 36 = a(5)^2.
binomial(12,6)/(3*7*11) = 924/231 = 4 = a(6)^2.
binomial(14,7)/(2*3*11*13) = 3432/858 = 4 = a(7)^2.
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MAPLE
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A000188:= n -> mul(t[1]^floor(t[2]/2), t = ifactors(n)[2]):
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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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