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%I #6 May 26 2024 21:41:40
%S 1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,1,1,0,0,0,1,1,0,0,0,0,1,0,1,1,0,0,
%T 0,0,1,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,1,1,1,0,0,0,0,0,1,0,
%U 0,0,1,0,1,0,0,0,1,0,1,1,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,1
%N a(n) = 1 if A276085(n) is a multiple of 5, otherwise 0, where A276085 is the primorial base log-function.
%H Antti Karttunen, <a href="/A373139/b373139.txt">Table of n, a(n) for n = 1..100000</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%H <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%H <a href="/index/Pri#primorial_numbers">Index entries for sequences related to primorial numbers</a>
%F a(n) = [A276085(n) == 0 (mod 5)], where [ ] is the Iverson bracket.
%o (PARI)
%o A002110(n) = prod(i=1,n,prime(i));
%o A276085(n) = { my(f = factor(n)); sum(k=1, #f~, f[k, 2]*A002110(primepi(f[k, 1])-1)); };
%o A373139(n) = !(A276085(n)%5);
%Y Characteristic function of A373140.
%Y Cf. A002110, A276085.
%K nonn
%O 1
%A _Antti Karttunen_, May 26 2024
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