id:A165630 - OEIS Search Results

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Numbers n such that sigma(n)/phi(n)=25/9, where sigma=A000203, phi=A000010.

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8721, 10179, 21489, 99813, 203721, 228417, 229653, 250705, 268047, 609957, 1150713, 1343277, 2429283, 2835417, 2835807, 2881197, 3150333, 3230469, 3833181, 4679157, 4885569, 5673291, 6082527, 6302529, 6713637, 6819879 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`A subsequence of A011257. Contains the product m*n of relatively prime (gcd(m,n)=1) terms (m,n) in A164647 x A164648.`
	PROGRAM	`(PARI) for( i=1, 1e7, sigma(i)/eulerphi(i)==25/9 && print1(i", "))`
	CROSSREFS	`Sequence in context: A035909 A031852 A115614 this_sequence A067867 A110077 A061665` `Adjacent sequences: A165627 A165628 A165629 this_sequence A165631 A165632 A165633`
	KEYWORD	`nonn`
	AUTHOR	`F. Firoozbakht and M. F. Hasler (mhasler(AT)univ-ag.fr), Sep 23 2009`

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

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