A303933 - OEIS

%I #27 Oct 18 2018 10:24:21

%S 0,0,8,576,3913172

%N a(n) is the number of odd primitive abundant numbers with n distinct prime divisors.

%C The 6th term is possibly 59687996404445, but this is at present unverified. - _Jacob Liddy_, Oct 16 2018

%D Valdas Diciunas, On the number of odd primitive abundant numbers with five and six distinct prime factors, Vilnius Conference in Combinatorics and Number Theory, page 12, 2017.

%H Valdas Diciunas, <a href="https://klevas.mif.vu.lt/~valdas/Abundant_Numbers/Abundant.pdf">On the number of odd primitive abundant numbers with five and six distinct prime factors</a>, slides, 2017.

%H L. E. Dickson, <a href="http://www.jstor.org/stable/2370405">Finiteness of the odd perfect and primitive abundant numbers with n distinct prime factors</a>, American Journal of Mathematics 35 (1913), pp. 413-422.

%H Jacob Liddy, <a href="http://www.math.uakron.edu/~sf34/opans0_6.html">OPANS (Odd Primitive Abundant NumberS)</a>, 2018. The downloadable file is a Zip-archive, 640 Megabytes, uncompresses to 10 Gigabytes.

%Y Cf. A005231 (odd abundant), A006038 (odd primitive abundant).

%Y Row lengths of A188439.

%K hard,more,nonn

%O 1,3

%A _Jacob Liddy_, May 02 2018