A058663 - OEIS

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A058663

a(n)=GCD[n-1,n-Phi(n)].

0, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 7, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 23, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 3, 1, 1, 21, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,10`
	FORMULA	`a(n)=GCD[n-1, cototient(n)]=GCD[n-1, A051953(n)]`
	EXAMPLE	`n=15, n-1=14, cototient(15)=15-Phi(15)=7,a(15)=GCD[14,7]=7; For most n-s, among others for primes a(n)=1.`
	CROSSREFS	`A000010, A051953, A009195.` `Sequence in context: A140750 A028264 A010122 * A124371 A147989 A119329` `Adjacent sequences: A058660 A058661 A058662 * A058664 A058665 A058666`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Dec 28 2000`

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Last modified February 15 21:45 EST 2012. Contains 205860 sequences.