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Non-balanced numbers in A015763.
6

%I #15 Apr 11 2024 04:06:41

%S 46,134,138,161,184,230,299,322,402,414,483,552,598,623,644,670,690,

%T 805,874,897,966,1173,1196,1208,1242,1246,1288,1495,1608,1610,1702,

%U 1794,1869,1909,1932,1990,1992,2010,2024,2070,2185,2202,2346,2415,2576

%N Non-balanced numbers in A015763.

%H Amiram Eldar, <a href="/A074866/b074866.txt">Table of n, a(n) for n = 1..10000</a>

%F sigma_5(a(n)) mod phi(a(n)) = 0; sigma(a(n)) mod phi(a(n)) <> 0.

%t q[n_] := Sign[Mod[DivisorSigma[{1, 5}, n], EulerPhi[n]]] == {1, 0}; Select[Range[3000], q] (* _Amiram Eldar_, Apr 11 2024 *)

%o (PARI) is(n) = {my(f = factor(n), phi = eulerphi(f)); (sigma(f) % phi) && !(sigma(f, 5) % phi);} \\ _Amiram Eldar_, Apr 11 2024

%Y Cf. A000010, A000203, A001160, A015763, A020492, A078539.

%Y Cf. A074868, A077801, A077803, A078544, A078549, A078550.

%K nonn

%O 1,1

%A _Labos Elemer_, Dec 05 2002