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A373246 Greatest common divisor of n and its prime shadow: a(n) = gcd(n, A181819(n)).

%I A373246 #9 May 30 2024 16:57:36
%S A373246 1,2,1,1,1,2,1,1,3,2,1,6,1,2,1,1,1,6,1,2,1,2,1,2,1,2,1,2,1,2,1,1,1,2,
%T A373246 1,9,1,2,1,10,1,2,1,2,3,2,1,2,1,2,1,2,1,2,1,2,1,2,1,12,1,2,3,1,1,2,1,
%U A373246 2,1,2,1,3,1,2,3,2,1,2,1,2,1,2,1,12,1,2,1,2,1,6,1,2,1,2,1,2,1,2,3,1,1,2,1,2,1
%N A373246 Greatest common divisor of n and its prime shadow: a(n) = gcd(n, A181819(n)).
%H A373246 Antti Karttunen, <a href="/A373246/b373246.txt">Table of n, a(n) for n = 1..65537</a>
%F A373246 a(n) = gcd(A181819(n), A373247(n)).
%F A373246 a(n) = A181819(n) / A373249(n).
%o A373246 (PARI)
%o A373246 A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));
%o A373246 A373246(n) = gcd(n, A181819(n));
%Y A373246 Cf. A181819, A373247, A373249.
%Y A373246 Cf. A325755 [numbers k for which a(k) = A181819(k)], A353566 (their characteristic function).
%K A373246 nonn
%O A373246 1,2
%A A373246 _Antti Karttunen_, May 29 2024