A157353 Products (semiprimes) of two distinct primes that are not safe primes.

6, 26, 34, 38, 39, 51, 57, 58, 62, 74, 82, 86, 87, 93, 106, 111, 122, 123, 129, 134, 142, 146, 158, 159, 178, 183, 194, 201, 202, 206, 213, 218, 219, 221, 226, 237, 247, 254, 262, 267, 274, 278, 291, 298, 302, 303, 309, 314, 323, 326, 327, 339, 346, 362, 377

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Feb 27 2009

Keywords

• nonn

Examples

			6=2*3; 2 and 3 are not safe primes.
26=2*13; 2 and 13 are not safe primes.
		

Crossrefs

Cf. A001358, A005384, A005385, A006881, A007304, A111206, A157342, A157344, A157345, A157346, A157347, A157352.

Programs

Mathematica

lst={};Do[If[Plus@@Last/@FactorInteger[n]==2,a=Length[First/@FactorInteger[n]];If[a==2,b=First/@FactorInteger[n];c=b[[1]];d=b[[2]];If[ !PrimeQ[(c-1)/2]&&!PrimeQ[(d-1)/2],AppendTo[lst,n]]]],{n,7!}];lst