|
|
A063870
|
|
Numbers n such that sigma(n) - usigma(n) = 3n/2.
|
|
1
|
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
PROG
|
(PARI) u(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)); for(n=1, 10000, if(sigma(n)-u(n)==3*n/2, print(n)))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
There are no others less than 1.5*10^13, but here's a larger one: 948990933336933380096. - Dean Hickerson, Sep 25 2001
|
|
STATUS
|
approved
|
|
|
|