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A164647
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Numbers n such that sigma(n)/phi(n) = 16/9.
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3
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1463, 2945, 8255, 70091, 81809, 89999, 122759, 187625, 193039, 196469, 388585, 494665, 671365, 2311673, 2442583, 2687113, 4209985, 4705285, 4902247, 5393017, 5667389, 5866003, 9248323, 10795967, 11345411, 11670275, 11773027, 13290485, 13741273, 15978487
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OFFSET
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1,1
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COMMENTS
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A subsequence of A011257.
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LINKS
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Donovan Johnson, Table of n, a(n) for n = 1..1000
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PROG
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(PARI) for( n=1, 10^7, sigma(n)==16/9*eulerphi(n) && print1(n", "))
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CROSSREFS
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Cf. A000010 (=phi), A000203 (=sigma), A068390, A163667, A164646.
Sequence in context: A251943 A251950 A023074 * A284887 A237483 A280906
Adjacent sequences: A164644 A164645 A164646 * A164648 A164649 A164650
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KEYWORD
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nonn
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AUTHOR
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M. F. Hasler, Aug 22 2009
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EXTENSIONS
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More terms from Farideh Firoozbakht, Sep 22 2009
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STATUS
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approved
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