OFFSET
1,1
COMMENTS
FORMULA
For squarefree n = p1*p2*...*pj, a(n) = 1+lcm(p1-1, p2-1, ..., pj-1).
EXAMPLE
a(35) = 13 because 35 divides 1^13-1, 2^13-2, 3^13-3, etc.; but 35 does not divide 2^2-2, 2^3-3, 2^4-2, ..., 2^11-2 or 2^12-2.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Franz Vrabec, Aug 09 2004
EXTENSIONS
Edited and extended by David Wasserman, Oct 30 2007
STATUS
approved