

A063513


Least balanced numbers (A020492): m such that the quotient sigma(m)/phi(m) equals the nth prime.


0



3, 2, 56, 12, 2580, 630, 416640, 291060, 1719277560, 587133466920, 33044291280
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

Table of n, a(n) for n=1..11.


FORMULA

a(n) = Min{x : A000203(x)/A000010(x) = p(n)} = Min{x : A023897(x) = p(n)}


EXAMPLE

n=7: p(7) = 17. a(7) = 416640 = 2^7*3*5*7*31. sigma(416640) = 1566720 = 17*phi(a(7)). phi(416640) = 92160.


CROSSREFS

Cf. A055234 (smallest x such that sigma(x) = n*phi(x)), A000203, A000010, A020492, A023897.
Sequence in context: A104254 A231576 A190286 * A265635 A265619 A298021
Adjacent sequences: A063510 A063511 A063512 * A063514 A063515 A063516


KEYWORD

nonn,more


AUTHOR

Labos Elemer, Jul 31 2001


EXTENSIONS

More terms from Robert G. Wilson v, Aug 09 2001
a(10)a(11) (from A055234) added by Donovan Johnson, Feb 03 2012


STATUS

approved



