OFFSET
1,7
COMMENTS
phi(c, n) = 0 iff n is in A048597.
LINKS
Reikku Kulon, Table of n, phi(2, n) for n = 1..10000
EXAMPLE
phi(2, 7) = 2: the two semiprimes less than 7 are 4 and 6.
phi(2, 15) = 2: there are five semiprimes less than 15 (4, 6, 9, 10, 14), but only 4 and 14 are relatively prime to 15.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Reikku Kulon, Sep 20 2008
STATUS
approved