OFFSET
1,2
COMMENTS
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000
EXAMPLE
a(4) = 3 because 4 and 2 are not coprime and {1,3,4} is a maximal subset of {1,2,3,4} with pairwise coprime elements.
a(9) = 5, the maximal subsets are {1,2,5,7,9}, {1,4,5,7,9}, {1,5,7,8,9}.
MAPLE
with(numtheory):
a:= n-> `if`(n<4, n, pi(n) -nops(factorset(n)) +2):
seq(a(n), n=1..120);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Mar 01 2011
STATUS
approved