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

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 *)

Prog

(PARI) isok(n) = (sigma(n) % (eulerphi(n) + 6)) == 0; \\ Michel Marcus, Jul 15 2017

Crossrefs

Cf. A000010, A000203.

Sequence in context: A129216 A259536 A067796 * A293184 A368408 A064974

Adjacent sequences: A015794 A015795 A015796 * A015798 A015799 A015800

Keyword

nonn

Author

Robert G. Wilson v

Extensions

More terms from Jud McCranie, Dec 25 1999

a(32)-a(34) from Donovan Johnson, Feb 28 2012

Status

approved