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A111207
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Numbers that are both Sophie Germain semiprimes and semi-Sophie Germain semiprimes.
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1
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4, 10, 25, 46, 55, 106, 123, 145, 159, 205, 226, 267, 339, 358, 415, 466, 529, 573, 583, 718, 753, 843, 865, 979, 1077, 1195, 1243, 1257, 1293, 1366, 1405, 1465, 1473, 1486, 2098, 2157, 2206, 2427, 2455, 2545, 2563, 2581, 2599, 2629, 2809, 2818, 2998, 3057
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| This is the intersection of the sequence of Sophie Germain semiprimes (A111153) and semi-Sophie Germain semiprimes (A111206).
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EXAMPLE
| a(4)=46 because 46 is the 4th semiprime such that 2*46+1=93 is a semiprime and both of its factors are Sophie.
Germain primes: 2*2+1=5 and 2*23+1=47.
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CROSSREFS
| Cf. A111153, A001358, A005384, A111206.
Sequence in context: A051864 A111153 A145368 * A113412 A159297 A033539
Adjacent sequences: A111204 A111205 A111206 * A111208 A111209 A111210
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KEYWORD
| nonn
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AUTHOR
| Christopher M. Tomaszewski (cmt1288(AT)comcast.net), Oct 24 2005
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EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 31 2005
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