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A015870
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Numbers k such that phi(k + 4) | sigma(k) + 4.
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0
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6, 11, 12, 62, 65, 166, 251, 782, 2342, 6662, 25040, 83623931, 933180002, 943169410, 1840122962, 4294967291
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OFFSET
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1,1
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COMMENTS
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There are no other terms < 4290000000. - Jud McCranie, Dec 26 1999
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LINKS
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EXAMPLE
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phi(6+4)=4, which divides 16=sigma(6)+4, so 6 is a term of the sequence.
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MATHEMATICA
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Select[Range[100000],
Divisible[DivisorSigma[1, #] + 4, EulerPhi[# + 4]] &] (* David Nacin, Feb 28 2012 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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