OFFSET
1,4
LINKS
Nathaniel Johnston, Table of n, a(n) for n = 1..200
EXAMPLE
n = 5: 5! = 120, 120' = 244, gcd(120,244) = 4 -> a(5) = 4
CROSSREFS
KEYWORD
nonn
AUTHOR
Giorgio Balzarotti, Apr 16 2011
STATUS
approved