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%I #12 Jan 06 2023 10:51:29
%S 0,0,0,1,0,0,0,1,1,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,1,0,1,1,0,0,0,1,0,0,
%T 0,0,0,0,0,1,0,0,0,1,1,0,0,1,1,1,0,1,0,1,0,1,0,0,0,1,0,0,1,1,0,0,0,1,
%U 0,0,0,0,0,0,1,1,0,0,0,1,1,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,1,1,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,1,0,0,1,1
%N a(n) = A353459(n) mod 2.
%H Antti Karttunen, <a href="/A359469/b359469.txt">Table of n, a(n) for n = 1..100000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F For all n >= 1, a(n) = a(A003961(n)) = a(A348717(n)).
%o (PARI)
%o A353457(n) = { my(f=factor(n)); prod(i=1,#f~,if(!(primepi(f[i,1])%2), 1, if(f[i,2]==1, -1, 0))); };
%o A353458(n) = { my(f=factor(n)); prod(i=1,#f~,if(primepi(f[i,1])%2, 1, if(f[i,2]==1, -1, 0))); };
%o A353459(n) = (A353457(n)+A353458(n));
%o A359469(n) = (A353459(n)%2);
%o (Python)
%o from functools import reduce
%o from operator import iand
%o from sympy import factorint, primepi
%o def A359469(n):
%o f = [(primepi(p)&1, int(e==1)) for p, e in factorint(n).items()]
%o return reduce(iand,(e for p, e in f if not p),1)^reduce(iand,(e for p, e in f if p),1) # _Chai Wah Wu_, Jan 06 2023
%Y Characteristic function of A359470.
%Y Cf. A003961, A348717, A353457, A353458, A353459.
%Y Differs from A359466 and A359467 for the first time at n=100, as here a(100) = 1.
%K nonn
%O 1
%A _Antti Karttunen_, Jan 04 2023
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