login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

a(n) = 1 if A071324(n) is equal to A206369(n), otherwise 0; characteristic function of A317923.
4

%I #10 Jul 05 2021 05:46:32

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

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

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

%N a(n) = 1 if A071324(n) is equal to A206369(n), otherwise 0; characteristic function of A317923.

%H Antti Karttunen, <a href="/A345064/b345064.txt">Table of n, a(n) for n = 1..65537</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%F a(n) = [A071324(n) = A206369(n)], where [ ] is the Iverson bracket.

%F a(n) = [A345062(n)==1] * [A345063(n)==1].

%F a(n) = 1 iff A345060(n) = 0.

%F a(n) >= A010055(n) for all n.

%o (PARI)

%o A071324(n) = my(d=Vecrev(divisors(n))); sum(k=1, #d, (-1)^(k+1)*d[k]); \\ From A071324

%o A206369(n) = sumdiv(n, d, eulerphi(n/d) * issquare(d)); \\ From A206369

%o A345064(n) = (A071324(n)==A206369(n));

%Y Characteristic function of A317923.

%Y Cf. A010055, A071324, A206369, A345060, A345061, A345062, A345063.

%K nonn

%O 1

%A _Antti Karttunen_, Jun 07 2021