|
%I #9 May 31 2024 22:12:41
%S 0,0,1,1,1,1,0,1,0,0,1,1,1,1,0,0,0,1,0,1,0,1,1,1,0,1,0,0,0,1,1,1,0,0,
%T 1,0,0,1,0,1,0,1,0,1,0,0,1,1,1,0,0,0,0,1,0,1,0,1,1,1,0,1,0,0,0,0,1,1,
%U 0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,1,1,1,0,0,0,1,0,0,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,1
%N a(n) = 1 if A003415(n) == +1 (mod 3), otherwise 0, where A003415 is the arithmetic derivative.
%H Antti Karttunen, <a href="/A373254/b373254.txt">Table of n, a(n) for n = 0..100000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = [A003415(n) == +1 (mod 3)], where [ ] is the Iverson bracket.
%o (PARI)
%o A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A373254(n) = (1==(A003415(n)%3));
%Y Characteristic function of A373255.
%Y Cf. A003415, A373253.
%K nonn
%O 0
%A _Antti Karttunen_, May 31 2024
|
