A157346 Products of 3 distinct Sophie Germain primes.

30, 66, 110, 138, 165, 174, 230, 246, 290, 318, 345, 410, 435, 498, 506, 530, 534, 615, 638, 678, 759, 786, 795, 830, 890, 902, 957, 1038, 1074, 1130, 1146, 1166, 1245, 1265, 1310, 1334, 1335, 1353, 1398, 1434, 1506, 1595, 1686, 1695, 1730, 1749, 1758, 1790

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Feb 27 2009

Keywords

• nonn

Examples

			30 = 2*3*5; 2,3 and 5 are distinct Sophie Germain primes.
66 = 2*3*11; 2,3 and 11 are distinct Sophie Germain primes.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A001358, A005384, A111206, A157342, A006881, A157344, A157345, A007304.

Programs

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,7!}];lst
With[{sgps=Select[Prime[Range[100]],PrimeQ[2#+1]&]},Take[Union[ Times@@@ Subsets[sgps,{3}]],60]] (* Harvey P. Dale, Aug 10 2011 *)