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A015783
Numbers k such that phi(k) + 4 | sigma(k + 4).
5
6, 10, 20, 22, 34, 35, 50, 51, 56, 58, 66, 72, 82, 116, 118, 142, 195, 200, 202, 214, 220, 274, 298, 330, 340, 358, 382, 394, 454, 478, 538, 562, 622, 642, 668, 680, 694, 838, 862, 922, 940, 1042, 1056, 1138, 1198, 1234, 1272, 1282, 1295, 1318
OFFSET
1,1
LINKS
MATHEMATICA
Select[Range[1500], Divisible[DivisorSigma[1, #+4], EulerPhi[#]+4] &] (* Amiram Eldar, Dec 25 2023 *)
PROG
(PARI) is(n)=!(sigma(n+4)%(eulerphi(n)+4)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
Sequence in context: A327410 A145351 A227874 * A356055 A300020 A068017
KEYWORD
nonn
EXTENSIONS
Corrected by Charles R Greathouse IV, Sep 25 2012
STATUS
approved