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A157346 Products of 3 distinct Sophie Germain primes. +0
9
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 (list; graph; listen)
OFFSET

1,1

COMMENT

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,...

MAPLE

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

CROSSREFS

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

Sequence in context: A132771 A044132 A044513 this_sequence A154055 A064623 A112343

Adjacent sequences: A157343 A157344 A157345 this_sequence A157347 A157348 A157349

KEYWORD

nonn

AUTHOR

Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 27 2009

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Last modified November 24 14:25 EST 2009. Contains 167438 sequences.


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