cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

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%I A186963 #14 Jun 02 2025 03:57:25
%S A186963 2,2,2,3,4,3,4,5,4,4,6,5,6,7,6,7,6
%N A186963 Number of prime factors in the expansion of the infinitary perfect number A007357(n) over distinct terms of A050376.
%C A186963 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 A186963 a(n) = A162642(A007357(n)). - R. J. Mathar, Mar 30 2011
%e A186963 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 A186963 Cf. A007357, A050376, A187043
%K A186963 nonn
%O A186963 1,1
%A A186963 _Vladimir Shevelev_, Mar 02 2011