cp's OEIS Frontend

A325375 a(n) = gcd(A325319(n), A325320(n)).

%I A325375 #7 Apr 22 2019 18:07:05
%S A325375 3,1,9,1,3,1,1,3,3,1,9,1,1,7,1,5,9,1,1,1,3,1,1,3,1,1,3,1,3,9,1,1,1,1,
%T A325375 3,1,1,1,9,1,1,1,7,1,1,9,1,3,5,3,3,9,1,1,1,3,1,3,1,5,1,1,3,1,1,1,1,1,
%U A325375 1,3,3,1,1,3,1,1,1,3,3,1,25,1,1,9,1,1,9,1,3,1,27,1,1,1,1,3,9,1,49,1,1,1,1,1,1
%N A325375 a(n) = gcd(A325319(n), A325320(n)).
%H A325375 Antti Karttunen, <a href="/A325375/b325375.txt">Table of n, a(n) for n = 1..25000</a>
%F A325375 a(n) = gcd(A325319(n), A325320(n)).
%o A325375 (PARI)
%o A325375 up_to = 25000;
%o A325375 isA228058(n) = if(!(n%2)||(omega(n)<2),0,my(f=factor(n),y=0); for(i=1,#f~,if(1==(f[i,2]%4), if((1==y)||(1!=(f[i,1]%4)),return(0),y=1), if(f[i,2]%2, return(0)))); (y));
%o A325375 A228058list(up_to) = { my(v=vector(up_to), k=0, n=0); while(k<up_to, n++; if(isA228058(n), k++; v[k] = n)); (v); };
%o A325375 v228058 = A228058list(up_to);
%o A325375 A228058(n) = v228058[n];
%o A325375 A048250(n) = factorback(apply(p -> p+1,factor(n)[,1]));
%o A325375 A325313(n) = (A048250(n) - n);
%o A325375 A162296(n) = sumdiv(n, d, d*(1-issquarefree(d)));
%o A325375 A325314(n) = (n - A162296(n));
%o A325375 A325319(n) = -A325313(A228058(n));
%o A325375 A325320(n) = -A325314(A228058(n));
%o A325375 A325375(n) = gcd(A325319(n),A325320(n));
%Y A325375 Cf. A228058, A325319, A325320, A325376.
%K A325375 nonn
%O A325375 1,1
%A A325375 _Antti Karttunen_, Apr 22 2019