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 A204455 Squarefree product of all odd primes dividing n, and 1 if n is a power of 2: A099985/2. 10

%I

%S 1,1,3,1,5,3,7,1,3,5,11,3,13,7,15,1,17,3,19,5,21,11,23,3,5,13,3,7,29,

%T 15,31,1,33,17,35,3,37,19,39,5,41,21,43,11,15,23,47,3,7,5,51,13,53,3,

%U 55,7,57,29,59,15,61,31,21,1,65,33,67,17,69,35,71,3

%N Squarefree product of all odd primes dividing n, and 1 if n is a power of 2: A099985/2.

%C There are no odd primes dividing n iff n is a power of 2.

%C This sequence coincides with the bisection of A007947 (even indices), which is A099985, dividing out the even prime 2 in the squarefree kernel.

%F a(n) = A099985(n)/2 = A007947(2*n)/2.

%F a(n) = A000265(A007947(n)) = A007947(A000265(n)). - From _Charles R Greathouse IV_, Jan 19 2012.

%e a(5)=5 because 5 is a single odd prime.

%e a(9)=3 because 9=3*3 has as squarefree part 3.

%e a(1)=1 because 1 is a power of 2, having no odd primes as a factor.

%Y Cf. A099985, A099984, A007947, A000265.

%K nonn,mult,changed

%O 1,3

%A _Wolfdieter Lang_, Jan 19 2012

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