A140965 Smallest multiple of n with a number of divisors >= n.

1, 2, 6, 8, 20, 12, 42, 24, 36, 60, 132, 60, 312, 168, 120, 240, 612, 180, 912, 240, 420, 660, 1380, 360, 900, 1560, 1080, 840, 3480, 720, 3720, 1440, 1980, 3060, 1260, 1260, 8880, 4560, 3120, 1680, 14760, 2520, 15480, 3960, 2520, 8280, 16920, 3360, 8820

Offset

1,2

Comments

Also add a(n)/n as a separate sequence; first 8 terms are 1,1,2,2,4,2,6,3.

Links

Table of n, a(n) for n=1..49.

Example

a(8) = 24 because 8 has only 4 divisors and 16 has only 5, but 24 has 8 and so 24 qualifies.

Mathematica

a = {}; For[n = 1, n < 50, n++, i = 1; While[DivisorSigma[0, i*n] < n, i++ ]; AppendTo[a, n*i]]; a (* Stefan Steinerberger, Aug 28 2008 *)

Crossrefs

Sequence in context: A028332 A183171 A124827 * A002618 A135616 A069553

Adjacent sequences: A140962 A140963 A140964 * A140966 A140967 A140968

Keyword

nonn

Author

J. Lowell, Jul 27 2008

Extensions

More terms from Stefan Steinerberger, Aug 28 2008

Status

approved