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%I #16 Aug 22 2017 20:18:18
%S 20,24,40,48,60,80,96,120,140,156,160,180,192,240,260,272,280,312,320,
%T 336,340,360,384,408,420,460,468,480,520,540,544,560,580,600,624,640,
%U 672,680,696,720,740,768,780
%N Numbers n such that A263014(n) > 0.
%H Hans Havermann, <a href="/A263016/b263016.txt">Table of n, a(n) for n = 1..530</a>
%t sumin[n_, k_] := Mod[Sum[If[GCD[i, n] == 1, PowerMod[i, k, n], 0], {i, 1, n}], n]; Select[Range[100], sumin[#, #] > 0 &]
%Y Cf. A263014, A263015, A290287.
%K nonn
%O 1,1
%A _José María Grau Ribas_, Oct 07 2015