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A165630 Numbers n such that sigma(n)/phi(n)=25/9, where sigma=A000203, phi=A000010. 1
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; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

A subsequence of A011257. Contains the product m*n of relatively prime (gcd(m,n)=1) terms (m,n) in A164647 x A164648.

PROG

(PARI) for( i=1, 1e7, sigma(i)/eulerphi(i)==25/9 && print1(i", "))

CROSSREFS

Sequence in context: A035909 A031852 A115614 * A067867 A110077 A203377

Adjacent sequences:  A165627 A165628 A165629 * A165631 A165632 A165633

KEYWORD

nonn

AUTHOR

F. Firoozbakht and M. F. Hasler (www.univ-ag.fr/~mhasler), Sep 23 2009

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Last modified February 17 12:38 EST 2012. Contains 206021 sequences.