OFFSET
2,3
COMMENTS
Note that a different sequence could be defined by "Number of positive numbers < n that do not have any anti-divisor as a factor," which gives A066452. Consider for example n=10 with anti-divisors {3,4,7} and the number 2. 2 is not coprime to the anti-divisor 4 and does not contribute to a(10), whereas 2 does not have 4 as a factor and contributes to A066452.
EXAMPLE
10 has anti-divisors {3,4,7}. The positive integers that are <10 and coprime to
all of them are {1,5}, so a(10)=2. The integers 2, 3, 4, 6, 7, 8 and 9
are not coprime to all of {3,4,7} and do not contribute to the count.
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Aug 07 2014
STATUS
approved