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A077803

Non-balanced numbers in A015769.

235, 329, 470, 658, 695, 705, 799, 807, 940, 987, 1316, 1390, 1410, 1529, 1598, 1614, 1645, 1786, 1880, 1969, 1974, 2085, 2115, 2397, 2632, 2734, 2820, 3055, 3058, 3290, 3478, 3938, 3948, 4136, 4170, 4230, 4465, 4587, 4794, 4935, 5264, 5358, 5593, 5640

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OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

sigma_11(a(n)) mod phi(a(n)) = 0; sigma(a(n)) mod phi(a(n)) <> 0.

MATHEMATICA

q[n_] := Sign[Mod[DivisorSigma[{1, 11}, n], EulerPhi[n]]] == {1, 0}; Select[Range[6000], q] (* Amiram Eldar, Apr 11 2024 *)

PROG

(PARI) is(n) = {my(f = factor(n), phi = eulerphi(f)); (sigma(f) % phi) && !(sigma(f, 11) % phi); } \\ Amiram Eldar, Apr 11 2024

CROSSREFS