A015797 - OEIS

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A015797

Numbers n such that phi(n) + 6 | sigma(n).

14, 20, 54, 56, 234, 286, 456, 686, 735, 980, 1176, 1224, 1470, 2000, 3296, 21645, 34632, 37496, 43290, 46620, 62336, 191616, 277808, 779568, 1124528, 4095712, 16726016, 17409376, 50251776, 149911936, 177383296, 12883623936, 42932880896, 295964664896

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OFFSET

1,1

COMMENTS

a(35) > 10^12. - Donovan Johnson, Feb 28 2012

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

phi(14)+6 = 12, which divides sigma(14)=24, so 14 is in the sequence.

MATHEMATICA

Select[Range[100000],

Divisible[DivisorSigma[1, #], EulerPhi[#] + 6] &] (* David Nacin, Feb 28 2012 *)