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A015793
Numbers n such that phi(n) + 4 divides sigma(n).
2
6, 15, 21, 24, 30, 33, 39, 42, 51, 57, 66, 69, 78, 84, 87, 93, 96, 102, 108, 111, 114, 120, 123, 129, 138, 141, 159, 174, 175, 177, 183, 186, 201, 213, 219, 220, 222, 237, 246, 249, 258, 267, 282, 291, 303, 309, 318, 321, 327, 339, 350, 354, 366
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[400], Divisible[DivisorSigma[1, #], EulerPhi[#]+4]&] (* Harvey P. Dale, Aug 05 2014 *)
PROG
(PARI) is(n)=!(sigma(n)%eulerphi(n+4)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
Sequence in context: A012412 A009092 A330205 * A373899 A261078 A063466
KEYWORD
nonn
STATUS
approved