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%I #9 Jul 08 2024 16:41:09
%S 0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,
%T 1,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,1,0,0,1,
%U 0,0,0,1,0,1,0,0,1,1,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,0,1,0,1,0,0,1,0,0,1,0,0,1,1
%N a(n) = 1 if sigma(n) and sopfr(n) are both multiples of 3, otherwise 0, where sigma is the sum of divisors, and sopfr is the sum of prime factors with repetition.
%H Antti Karttunen, <a href="/A374222/b374222.txt">Table of n, a(n) for n = 1..100000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = A079978(A374126(n)).
%F a(n) = (1-A353815(n)) * A373371(n).
%F a(3*n) = a(n).
%o (PARI)
%o A001414(n) = ((n=factor(n))[, 1]~*n[, 2]);
%o A374222(n) = (!(sigma(n)%3) && !(A001414(n)%3));
%Y Characteristic function of A374223.
%Y Cf. A000203, A001414, A079978, A353815, A373371, A374126.
%K nonn
%O 1
%A _Antti Karttunen_, Jul 08 2024
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