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%I #12 Jun 02 2022 10:09:19
%S 2,3,4,6,32,34,54,55,58,70,84,133,141,221,285,322,377,407,472,664,684,
%T 988,1149,1241,1505,1911,1978,2230,2590,2631,2906,2912,3498,6111,6579,
%U 7232,8559,11194,13181,13952,15323,15409,15564,17362,18215,18754,22328
%N Numbers k such that phi(k) divides (sigma(k+1) + sigma(k-1)).
%H Amiram Eldar, <a href="/A067244/b067244.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[23000],Divisible[DivisorSigma[1,#-1]+DivisorSigma[1,#+1], EulerPhi[#]]&] (* _Harvey P. Dale_, Oct 04 2016 *)
%Y Cf. A000010, A000203.
%K easy,nonn
%O 1,1
%A _Benoit Cloitre_, Feb 20 2002
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