OFFSET
1,1
LINKS
T. D. Noe, Table of n, a(n) for n = 1..1000
MAPLE
with(numtheory); A048968:=n->`if`(type(sigma(n)/tau(n), prime), n, NULL); seq(A048968(n), n=1..2400); # Wesley Ivan Hurt, Feb 04 2014
MATHEMATICA
Select[ Range[2400], PrimeQ[ DivisorSigma[1, #] / DivisorSigma[0, #] ]& ] (* Jean-François Alcover, Sep 24 2012 *)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
More terms from Jud McCranie
STATUS
approved