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a(1) = 0, and for n > 1, a(n) = 1 if the largest proper divisor of n is of the form 4k+3, otherwise 0.
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%I #7 Apr 22 2022 18:14:07

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

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

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

%N a(1) = 0, and for n > 1, a(n) = 1 if the largest proper divisor of n is of the form 4k+3, otherwise 0.

%H Antti Karttunen, <a href="/A353492/b353492.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) = 1 iff A353490(n) = 3, otherwise 0.

%o (PARI)

%o A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));

%o A353492(n) = (3==(A032742(n)%4));

%Y Cf. A032742, A353490, A353491.

%K nonn

%O 1

%A _Antti Karttunen_, Apr 22 2022