A107656 - OEIS

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A107656

Numbers n such that prime(n)=d(n)*phi(n)+1, where d(n) is number of positive divisors of n.

1, 2, 3, 4, 652245 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`There is no further term up to 5*10^7.`
	EXAMPLE	`652245 is in the sequence because prime(652245)=d(652245)*phi(652245)+1.`
	MATHEMATICA	`Do[If[Prime[n] == DivisorSigma[0, n]*EulerPhi[n] + 1, Print[n]], {n, 50000000}]`
	CROSSREFS	`Cf. A104905, A107657.` `Sequence in context: A062929 A038105 A143716 * A024595 A144804 A118308` `Adjacent sequences: A107653 A107654 A107655 * A107657 A107658 A107659`
	KEYWORD	`more,nonn`
	AUTHOR	`Farideh Firoozbakht (mymontain(AT)yahoo.com), Jun 06 2005`

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.