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A077803
Non-balanced numbers in A015769.
6
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
OFFSET
1,1
LINKS
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Dec 05 2002
STATUS
approved