OFFSET
1,5
COMMENTS
Nonnegative by considering the largest power of 2 up to n.
EXAMPLE
1/1 - 1/2 - 1/3 - 1/4 - 1/5 + 1/6 + 1/7 = 11/420 = 11/lcm(1,2,3,4,5,6,7), so a(7) <= 11; no other choice of signs yields 1/420, ..., 10/420, so a(7)=11.
CROSSREFS
KEYWORD
nonn
AUTHOR
Greg Martin (gerg(AT)math.toronto.edu), Apr 19 2001
EXTENSIONS
More terms from Naohiro Nomoto, Jun 24 2001
a(23)-a(41) from Giovanni Resta, Jun 12 2016
STATUS
approved