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A015782
Numbers k such that phi(k) + 3 | sigma(k + 3).
6
7, 10, 14, 21, 26, 34, 38, 58, 86, 93, 94, 106, 134, 146, 178, 194, 226, 254, 274, 278, 314, 334, 346, 357, 381, 386, 394, 398, 446, 454, 458, 538, 554, 566, 614, 674, 681, 698, 706, 758, 766, 794, 818, 878, 926, 934, 974, 1006, 1018, 1046
OFFSET
1,1
LINKS
MAPLE
filter:= proc(n) uses numtheory;
sigma(n+3) mod (3+phi(n)) = 0
end proc:
select(filter, [$1..2000]); # Robert Israel, Jan 24 2022
MATHEMATICA
Select[Range[1100], Divisible[DivisorSigma[1, #+3], EulerPhi[#]+3]&] (* Harvey P. Dale, Sep 04 2013 *)
PROG
(PARI) is(n)=!(sigma(n+3)%(eulerphi(n)+3)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
Sequence in context: A229306 A023485 A020721 * A336089 A154681 A225676
KEYWORD
nonn
EXTENSIONS
Corrected by Charles R Greathouse IV, Sep 25 2012
STATUS
approved