OFFSET
0,5
COMMENTS
lcm(1,2,..,n) = (n!*a(n)) / ((n/2)!*a(n/2))^2.
lcm(1,2,..,n)*a(n) is a divisor of n! and n!/(lcm(1,2,..,n)*a(n)) is a square.
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Feb 04 2012
STATUS
approved