OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[6 Range[0, 200] + 4, PrimeOmega[#] == 2&] (* Vincenzo Librandi, Sep 22 2012 *)
PROG
(Magma) IsSemiprime:=func<n | &+[d[2]: d in Factorization(n)] eq 2>; [s: n in [0..200] | IsSemiprime(s) where s is 6*n + 4]; // Vincenzo Librandi, Sep 22 2012
(Python)
from sympy import factorint
def semiprime(n): f = factorint(n); return sum(f[p] for p in f) == 2
print(list(filter(semiprime, range(4, 1115, 6)))) # Michael S. Branicky, Apr 10 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post and Ray Chandler, Oct 15 2005
STATUS
approved