

A212490


Least number m > 1 such that A000203(x)*x = m has exactly n solutions.


3




OFFSET

1,1


COMMENTS

6 = 6.
336 = 6*28*2.
333312 = 6*28*496*2*2.
5418319872 = 6*28*496*8128*2*2*2.


REFERENCES

R. K. Guy, Unsolved Problems in Theory of Numbers, SpringerVerlag, Third Edition, 2004, B11.


LINKS

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


EXAMPLE

For n=3, 333312 has exactly 3 solutions: sigma(434)*434 = 333312, sigma(372)*372 = 333312, and sigma(336)*336 = 333312; therefore a(3) = 333312.


CROSSREFS

Cf. A212489, A212327, A212373.
Sequence in context: A210769 A003031 A144849 * A047941 A229501 A289738
Adjacent sequences: A212487 A212488 A212489 * A212491 A212492 A212493


KEYWORD

nonn,more


AUTHOR

Naohiro Nomoto, May 18 2012


EXTENSIONS

a(5) from Donovan Johnson, May 20 2012


STATUS

approved



