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A066924 Numbers n such that the GCD of n and the Chowla's function of n (A048050) is >= n/3. 0
1, 4, 9, 36, 345, 6489, 88473 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No more terms below 10^9. - Amiram Eldar, Aug 28 2019

LINKS

Table of n, a(n) for n=1..7.

MATHEMATICA

Select[ Range[ 10^7 ], GCD[ #, DivisorSigma[ 1, # ] - # - 1 ] >= #/3 && !PrimeQ[ # ] & ]

PROG

(PARI) f(n) = if(n>1, sigma(n)-n-1, 0); \\ A048050

isok(n) = gcd(n, f(n)) > n/3; \\ Michel Marcus, Aug 28 2019

CROSSREFS

Cf. A048050, A074844.

Sequence in context: A077211 A073977 A055872 * A251689 A249101 A289157

Adjacent sequences:  A066921 A066922 A066923 * A066925 A066926 A066927

KEYWORD

nonn,more

AUTHOR

Robert G. Wilson v, Jan 23 2002

STATUS

approved

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Last modified April 10 06:23 EDT 2020. Contains 333392 sequences. (Running on oeis4.)