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Number of prime factors in the expansion of the infinitary perfect number A007357(n) over distinct terms of A050376
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%I #12 Mar 30 2012 18:52:59

%S 2,2,2,3,4,3,4,5,4,4,6,5,6,7,6,7,6

%N Number of prime factors in the expansion of the infinitary perfect number A007357(n) over distinct terms of A050376

%C The total number of factors in the decomposition of A007357(n) in terms of A050376 is A187043(n). The subset of factors which are ordinary primes are counted here.

%F a(n) = A162642(A007357(n)). - R. J. Mathar, Mar 30 2011

%e The unique expansion of A007357(2)= 60 as a product of terms of A050376 is 3*4*5. Two of these factors, namely 3 and 5, are primes (A000040), so a(2)=2.

%Y Cf. A007357, A050376, A187043

%K nonn

%O 1,1

%A _Vladimir Shevelev_, Mar 02 2011