OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
40=2*2*2*5 (4-almost prime) and 2+2+2+5=11 is a prime.
PROG
(PARI) is(n)=my(f=factor(n)); sum(i=1, #f~, f[i, 2])==4 && isprime(sum(i=1, #f~, f[i, 1]*f[i, 2])) \\ Charles R Greathouse IV, Oct 11 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 12 2005
STATUS
approved