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A373249 a(n) = A181819(n) / gcd(n, A181819(n)), where A181819(n) is the prime shadow of n. 3

%I #9 May 30 2024 16:57:20

%S 1,1,2,3,2,2,2,5,1,2,2,1,2,2,4,7,2,1,2,3,4,2,2,5,3,2,5,3,2,4,2,11,4,2,

%T 4,1,2,2,4,1,2,4,2,3,2,2,2,7,3,3,4,3,2,5,4,5,4,2,2,1,2,2,2,13,4,4,2,3,

%U 4,4,2,5,2,2,2,3,4,4,2,7,7,2,2,1,4,2,4,5,2,2,4,3,4,2,4,11,2,3,2,9,2,4,2,5,8

%N a(n) = A181819(n) / gcd(n, A181819(n)), where A181819(n) is the prime shadow of n.

%H Antti Karttunen, <a href="/A373249/b373249.txt">Table of n, a(n) for n = 1..65537</a>

%F a(n) = A181819(n) / A373246(n) = A181819(n) / gcd(n, A181819(n)).

%o (PARI)

%o A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2])));

%o A373249(n) = { my(s=A181819(n)); s/gcd(n, s); };

%Y Cf. A181819, A373246.

%Y Cf. A325755 (positions of 1's), A353566 (their characteristic function).

%K nonn

%O 1,3

%A _Antti Karttunen_, May 30 2024

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Last modified August 22 10:30 EDT 2024. Contains 375369 sequences. (Running on oeis4.)