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A051644
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Primes of the form 6p+1 where p is also prime.
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6
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13, 19, 31, 43, 67, 79, 103, 139, 223, 283, 367, 439, 499, 607, 619, 643, 787, 823, 907, 1039, 1087, 1399, 1447, 1543, 1579, 1627, 1663, 1699, 1759, 1867, 1879, 1987, 2083, 2203, 2239, 2383, 2659, 2767, 2803, 3019, 3343, 3463, 3559, 3607, 3643, 3847, 3919
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Analogous to A005385; can be called 6-safe primes.
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FORMULA
| a(n) = 6*A007693(n) + 1.
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EXAMPLE
| 103 is here because it is prime and (103-1)/6=17 is prime.
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MATHEMATICA
| Select[1 + 6Prime@Range[120], PrimeQ] (*Chandler*)
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CROSSREFS
| Cf. A005384, A005385, A002476, A007693, A016921, A024899, A091178.
Sequence in context: A069324 A040047 A163847 * A101408 A023252 A128342
Adjacent sequences: A051641 A051642 A051643 * A051645 A051646 A051647
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu)
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EXTENSIONS
| Edited, corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 14 2007
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