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a(n) = 1 if A374200(n) = 1, otherwise 0, where A374200 is the minimum value of A347381 that it obtains among unitary divisors of n larger than 1.
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%I #6 Jul 09 2024 19:33:57

%S 0,0,1,1,1,0,0,0,0,0,0,1,0,0,1,0,0,0,0,1,1,0,0,1,0,0,0,0,0,0,0,0,1,0,

%T 1,1,0,0,1,1,0,0,0,1,1,0,0,1,0,0,1,1,0,0,1,0,1,0,0,1,0,0,0,0,1,0,0,1,

%U 1,0,0,0,0,0,1,1,0,0,0,1,0,0,0,0,1,0,1,0,0,0,0,1,1,0,1,1,0,0,0,1,0,0,0,0,1,0,0,1,0,0,1,0,0,0,1,1,0,0,0,1,0,0,1,1,0

%N a(n) = 1 if A374200(n) = 1, otherwise 0, where A374200 is the minimum value of A347381 that it obtains among unitary divisors of n larger than 1.

%H Antti Karttunen, <a href="/A374220/b374220.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) = [A374200(n) = 1], where [ ] is the Iverson bracket.

%o (PARI)

%o A374200(n) = { my(m=-1,x); fordiv(n,d,if(d>1 && 1==gcd(d,n/d), x = A347381(d); if(m<0 || x<m, m=x))); if(-1==m,0,m); };

%o A374220(n) = (1==A374200(n));

%Y Characteristic function of A374221.

%Y Cf. A000203, A005940, A347381, A374200.

%K nonn

%O 1

%A _Antti Karttunen_, Jul 09 2024