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%I #9 Jun 30 2024 22:07:22
%S 1,0,1,1,1,0,1,0,0,0,1,0,1,0,0,1,1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,
%T 0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,1,1,0,1,0,
%U 1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,1,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1
%N a(n) = 1 if the number of divisors of n divides n-1, otherwise 0.
%H Antti Karttunen, <a href="/A373993/b373993.txt">Table of n, a(n) for n = 1..100000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%t A373993[n_] := Boole[Divisible[n - 1, DivisorSigma[0, n]]];
%t Array[A373993, 100] (* _Paolo Xausa_, Jun 30 2024 *)
%o (PARI) A373993(n) = !((n-1)%numdiv(n));
%Y Characteristic function of A354711.
%Y Cf. A000005.
%K nonn
%O 1
%A _Antti Karttunen_, Jun 30 2024
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