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A015831
Numbers k such that phi(k + 11) | sigma(k).
0
15, 21, 46, 69, 88, 94, 115, 119, 189, 204, 209, 210, 213, 255, 297, 329, 332, 399, 418, 465, 470, 589, 598, 609, 616, 663, 696, 749, 799, 869, 950, 1074, 1081, 1173, 1199, 1365, 1593, 1595, 1615, 1729, 1888, 1917, 2014, 2024, 2185, 2189, 2289, 2376, 2449
OFFSET
1,1
MATHEMATICA
Select[Range[3000], Divisible[DivisorSigma[1, #], EulerPhi[11 + #]] &] (* David Nacin, Mar 01 2012 *)
PROG
(PARI) is(n)=!(sigma(n)%eulerphi(n+11)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
Sequence in context: A247021 A334117 A129752 * A275169 A063176 A083372
KEYWORD
nonn
STATUS
approved