A063513 Least balanced numbers (A020492): m such that the quotient sigma(m)/phi(m) equals the n-th prime.

3, 2, 56, 12, 2580, 630, 416640, 291060, 1719277560, 587133466920, 33044291280

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: A231576 A336520 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