cp's OEIS Frontend

A325632 a(n) = gcd(n, A325634(n)) = gcd(n, A091255(n, sigma(n))).

%I A325632 #9 May 21 2019 22:03:08
%S A325632 1,1,1,1,1,6,1,1,1,2,1,4,1,2,3,1,1,3,1,2,1,2,1,12,1,2,1,28,1,6,1,1,3,
%T A325632 2,1,1,1,2,1,10,1,2,1,4,5,2,1,4,1,1,3,2,1,2,1,8,1,2,1,4,1,2,1,1,1,6,1,
%U A325632 2,1,14,1,9,1,2,1,4,1,2,1,2,1,2,1,28,5,2,1,4,1,2,1,4,1,2,5,12,1,1,1,1,1,2,1,2,3
%N A325632 a(n) = gcd(n, A325634(n)) = gcd(n, A091255(n, sigma(n))).
%H A325632 Antti Karttunen, <a href="/A325632/b325632.txt">Table of n, a(n) for n = 1..65537</a>
%H A325632 <a href="/index/Ge#GF2X">Index entries for sequences related to polynomials in ring GF(2)[X]</a>
%H A325632 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A325632 a(n) = gcd(n, A325634(n)) = gcd(n, A091255(n, A000203(n))).
%o A325632 (PARI)
%o A325632 A091255sq(a,b) = fromdigits(Vec(lift(gcd(Pol(binary(a))*Mod(1, 2),Pol(binary(b))*Mod(1, 2)))),2);
%o A325632 A325634(n) = A091255sq(n, sigma(n));
%o A325632 A325632(n) = gcd(n,A325634(n));
%Y A325632 Cf. A000203, A091255, A325634, A325639 (fixed points).
%Y A325632 Differs from A009194 for the first time at n=42, where a(42) = 2, while A009194(42) = 6.
%Y A325632 Differs from A325633 and A325640 for the first time at n=45, where a(45) = 5, while A325633(45) = 1 and A325640(45) = 3.
%K A325632 nonn
%O A325632 1,6
%A A325632 _Antti Karttunen_, May 21 2019