A186963 Number of prime factors in the expansion of the infinitary perfect number A007357(n) over distinct terms of A050376.

2, 2, 2, 3, 4, 3, 4, 5, 4, 4, 6, 5, 6, 7, 6, 7, 6

Offset: 1

Author

Vladimir Shevelev, Mar 02 2011

Keywords

• nonn

Comments

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.

Examples

			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.
		

Crossrefs

Cf. A007357, A050376, A187043

Formula

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