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A023243
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Numbers n such that n remains prime through 2 iterations of function f(x) = 2x + 5.
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2
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7, 13, 31, 37, 67, 73, 79, 139, 151, 181, 367, 541, 613, 661, 709, 739, 787, 811, 829, 997, 1087, 1117, 1123, 1249, 1327, 1669, 1753, 1801, 1861, 1999, 2011, 2113, 2179, 2239, 2293, 2473, 2557, 2659, 2713, 2719, 3037, 3181, 3187, 3271, 3301, 3517, 3727, 3793
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| n, 2*n+5, 4*n+15 are primes [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 04 2010]
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PROG
| (MAGMA) [n: n in [0..100000] | IsPrime(n) and IsPrime(2*n+5) and IsPrime(4*n+15)] [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 04 2010]
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CROSSREFS
| Sequence in context: A040084 A151723 A046139 * A087196 A074963 A110912
Adjacent sequences: A023240 A023241 A023242 * A023244 A023245 A023246
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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