OFFSET
2,1
COMMENTS
For the numbers, instead of the indices, see A110442. The last term, a(33), yields a 48361012-digit number having 6375908 prime factors.
EXAMPLE
a(4)=9 because the 9th colossally abundant number is c=55440 and sigma(c)/c = 4.18701 > 4, while the 8th colossally abundant number is c'=5040 and sigma(c')/c' = 3.838 < 4.
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Jul 20 2005
EXTENSIONS
Definition and example clarified by Jonathan Sondow, Dec 08 2011
STATUS
approved