OFFSET
1,1
COMMENTS
Least solutions of d(x)=A000005(x)=pq equation, where 1<p<q, primes: x=(2^q)*(3^p) where the exponent of smaller base[=2] is the larger prime factor[=q].
Since 2^(pq-1)>2^(q-1)*3^(p-1) -> [(2^q)/3]^(p-1) holds for q>1, p>1, therefore these solutions are in fact minimal.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..563
EXAMPLE
If d(x)=253=11*23, then 1<p=11<q=23,q-1=22,p-1=10, 2^22=4194304, 3^10=59049 so the smallest number x, which has 253 divisors is 4194304*59049=247669456896.
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, May 30 2001
STATUS
approved