id:A039777 - OEIS Search Results

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phi(a(n)) is equal to the sum of (the product of prime factors and the products of exponents) of (a(n)-1).

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2, 5, 21, 45, 285, 765, 27645, 196605, 41067645, 72787965 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Next term if it exists is >= 10^8.`
	EXAMPLE	`phi(21)=12, 20=2^25^1, (22)+(5*1)=20.`
	CROSSREFS	`Cf. A000010, A039696.` `Sequence in context: A006893 A003163 A088498 this_sequence A000941 A000131 A152801` `Adjacent sequences: A039774 A039775 A039776 this_sequence A039778 A039779 A039780`
	KEYWORD	`nonn,hard`
	AUTHOR	`Olivier Gerard (olivier.gerard(AT)gmail.com)`
	EXTENSIONS	`More terms from Jud McCranie (j.mccranie(AT)comcast.net)`

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Last modified December 3 22:15 EST 2009. Contains 170310 sequences.