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Numbers k such that A368405(k) = 0.
1

%I #8 Dec 24 2023 02:43:35

%S 2,22,28,34,42,44,110,114,140,198,202,204,376,380,500,646,690,692,694,

%T 840,842,856,858,866,868,876,878,880,896,898,900,902,910,914,916,1036,

%U 1038,1042,1044,1046,1048,1050,1052,1054,1066,1068,1076,1078,1080,1088,1090

%N Numbers k such that A368405(k) = 0.

%H Amiram Eldar, <a href="/A368406/b368406.txt">Table of n, a(n) for n = 1..10000</a>

%t f[p_, e_] := (-1)^DigitCount[e, 2, 1]; imu[1] = 1; imu[n_] := Times @@ f @@@ FactorInteger[n]; Position[Accumulate[Array[imu, 1000]], 0] // Flatten

%o (PARI) imu(n) = vecprod(apply(x -> (-1)^hammingweight(x), factor(n)[, 2]));

%o lista(n) = {my(s = 0); for(k = 1, n, s+ = imu(k); if(s == 0, print1(k, ", ")));}

%Y Cf. A028442, A275547, A368405.

%K nonn,easy

%O 1,1

%A _Amiram Eldar_, Dec 23 2023