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A329376 Multiplicative with a(p^e) = p when e == 2, otherwise a(p^e) = 1. 2

%I

%S 1,1,1,2,1,1,1,1,3,1,1,2,1,1,1,1,1,3,1,2,1,1,1,1,5,1,1,2,1,1,1,1,1,1,

%T 1,6,1,1,1,1,1,1,1,2,3,1,1,1,7,5,1,2,1,1,1,1,1,1,1,2,1,1,3,1,1,1,1,2,

%U 1,1,1,3,1,1,5,2,1,1,1,1,1,1,1,2,1,1,1,1,1,3,1,2,1,1,1,1,1,7,3,10,1,1,1,1,1

%N Multiplicative with a(p^e) = p when e == 2, otherwise a(p^e) = 1.

%C Product of those distinct prime factors that occur exactly twice in the prime factorization of n, that is, whose exponent is 2.

%H Antti Karttunen, <a href="/A329376/b329376.txt">Table of n, a(n) for n = 1..65537</a>

%F Multiplicative with a(p^e) = p when e == 2, otherwise a(p^e) = 1.

%F a(n) <= A000196(n).

%o (PARI) A329376(n) = { my(f = factor(n)); prod(i=1,#f~,f[i, 1]^(2 == f[i, 2])); };

%Y Cf. A000196.

%Y Row 3 of array A106177, and the square roots of its row 9.

%K nonn,mult

%O 1,4

%A _Antti Karttunen_, Nov 16 2019

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Last modified September 20 22:45 EDT 2021. Contains 347596 sequences. (Running on oeis4.)