OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..5600
EXAMPLE
1547 = 7*13*17 is a term: its prime factors 7, 13, and 17 are not Sophie Germain primes.
MATHEMATICA
lst={}; Do[If[Plus@@Last/@FactorInteger[n]==3, a=Length[First/@FactorInteger[n]]; If[a==3, b=First/@FactorInteger[n]; c=b[[1]]; d=b[[2]]; e=b[[3]]; If[ !PrimeQ[2*c+1]&&!PrimeQ[2*d+1]&&!PrimeQ[2*e+1], AppendTo[lst, n]]]], {n, 8!}]; lst
PROG
(Magma) S:=[ p: p in PrimesUpTo(120) | not IsPrime(2*p+1) ]; T:=[ q: a, b, c in S | a lt b and b lt c and q lt 10000 where q is a*b*c ]; Sort(~T); T; // Klaus Brockhaus, Apr 11 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Feb 27 2009
EXTENSIONS
Entries verified by Klaus Brockhaus, Apr 11 2009
STATUS
approved