A303933 a(n) is the number of odd primitive abundant numbers with n distinct prime divisors.

0, 0, 8, 576, 3913172

Offset

1,3

Comments

The 6th term is possibly 59687996404445, but this is at present unverified. - Jacob Liddy, Oct 16 2018

References

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.

Links

Table of n, a(n) for n=1..5.

Valdas Diciunas, On the number of odd primitive abundant numbers with five and six distinct prime factors, slides, 2017.

L. E. Dickson, Finiteness of the odd perfect and primitive abundant numbers with n distinct prime factors, American Journal of Mathematics 35 (1913), pp. 413-422.

Jacob Liddy, OPANS (Odd Primitive Abundant NumberS), 2018. The downloadable file is a Zip-archive, 640 Megabytes, uncompresses to 10 Gigabytes.

Crossrefs

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

Row lengths of A188439.

Sequence in context: A248706 A325292 A326552 * A188780 A015023 A225168

Adjacent sequences: A303930 A303931 A303932 * A303934 A303935 A303936

Keyword

hard,more,nonn

Author

Jacob Liddy, May 02 2018

Status

approved