|
| |
|
|
A157347
|
|
Products of 3 distinct non-Sophie Germain primes.
|
|
7
| |
|
|
1547, 1729, 2261, 2821, 3367, 3689, 3913, 4123, 4199, 4277, 4403, 4921, 5117, 5369, 5551, 5593, 5719, 6097, 6251, 6461, 6643, 6851, 7021, 7189, 7259, 7657, 7847, 7973, 8029, 8113, 8177, 8449, 8687, 8827, 8911, 9139, 9191, 9331, 9373, 9401, 9443, 9503
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| 1547=7*13*17; 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; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Apr 11 2009]
|
|
|
CROSSREFS
| Cf. A001358, A005384, A111206, A157342, A006881, A157344, A157345, A007304, A157346
Sequence in context: A133560 A038009 A090209 * A020408 A184683 A203501
Adjacent sequences: A157344 A157345 A157346 * A157348 A157349 A157350
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 27 2009
|
|
|
EXTENSIONS
| Entries verified by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Apr 11 2009
|
| |
|
|
