

A134639


Conjectured number of numbers k such that sigma(k)/k = n.


3




OFFSET

3,1


COMMENTS

These numbers come from Guy and Flammenkamp. Sequences A000396, A005820, A027687, A046060 and A046061 give the k for which the abundancy sigma(k)/k is 2, 3, 4, 5 and 6, respectively. Sequence A054030 gives the abundancy of each multiperfect number A007691.


REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, 3rd Ed., New York, SpringerVerlag, 2004, Section B2.


LINKS

Table of n, a(n) for n=3..7.
Achim Flammenkamp, The Multiply Perfect Numbers Page


CROSSREFS

Sequence in context: A207590 A226119 A036148 * A069497 A139249 A070150
Adjacent sequences: A134636 A134637 A134638 * A134640 A134641 A134642


KEYWORD

nonn,more


AUTHOR

T. D. Noe, Nov 05 2007


STATUS

approved



