OFFSET
1,8
PROG
(PARI) a(n)=if(n>3, my(f=factor(n)[, 1]); primepi(n)-primepi(f[#f]), 0) \\ Charles R Greathouse IV, Feb 21 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 04 2003
STATUS
approved