|
|
A107481
|
|
Number of different prime factors of the smallest n-perfect number.
|
|
1
|
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
a(4)=4 because the smallest 4-perfect number factorization is 2^5*3^3*5*7, which has 4 different prime factors.
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
Jose Brox (tautocrona(AT)terra.es), May 27 2005
|
|
STATUS
|
approved
|
|
|
|