A160598 - OEIS

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A160598

Numerator of coresilience C(n) = (n-eulerphi(n))/(n-1).

1, 1, 2, 1, 4, 1, 4, 3, 2, 1, 8, 1, 8, 1, 8, 1, 12, 1, 12, 9, 4, 1, 16, 5, 14, 9, 16, 1, 22, 1, 16, 13, 6, 11, 24, 1, 20, 15, 8, 1, 30, 1, 24, 21, 8, 1, 32, 7, 30, 19, 28, 1, 36, 5, 32, 3, 10, 1, 44, 1, 32, 27, 32, 17, 46, 1, 36, 25, 2, 1, 48, 1, 38, 35, 8, 17, 54, 1, 48, 27, 14, 1, 60, 1 (list; graph; refs; listen; history; internal format)

	OFFSET	`2,3`
	COMMENTS	`Obviously C(p)=1/(p-1), i.e. a(p)=1, for all primes p. Sequence A160599 lists composite numbers for which this is the case.`
	LINKS	`Project Euler, Problem 245: resilient fractions, May 2009`
	EXAMPLE	`a(10)=2 since for n=10, we have (n-eulerphi(n))/(n-1) = (10-4)/9 = 2/3.`
	PROG	`(PARI) A160598(n)=numerator((n-eulerphi(n))/(n-1))`
	CROSSREFS	`Cf. A160595-A160599.` `Sequence in context: A029205 A072721 A035092 * A107457 A112350 A063717` `Adjacent sequences: A160595 A160596 A160597 * A160599 A160600 A160601`
	KEYWORD	`nonn`
	AUTHOR	`M. F. Hasler (www.univ-ag.fr/~mhasler), May 23 2009`

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Last modified February 14 14:07 EST 2012. Contains 205623 sequences.