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Search: id:A129621
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| A129621 |
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Primes p such that at least one of k-1 and k+1 is prime, where k = sum of the two neighboring primes of 3*p. |
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1
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| 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 37, 41, 43, 59, 61, 67, 71, 73, 83, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 173, 179, 181, 193, 197, 199, 227, 229, 239, 241, 257, 263, 269, 277, 281, 283, 293, 307, 311, 313, 317, 331, 347, 349, 353
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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29*3 = 87, neighboring primes are 83 and 89 which sum to 172; 173 is prime, hence 29 is in the sequence.
31*3 = 93, neighboring primes are 89 and 97 which sum to 186; neither 185 nor 187 is prime, hence 31 is not in the sequence.
1091*3 = 3273, neighboring primes are 3271 and 3299 which sum to 6570; both 6569 and 6571 are prime, hence 1091 is in the sequence.
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PROGRAM
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(PARI) {m=360; forprime(p=2, m, d=3*p; k=precprime(d)+nextprime(d); if(isprime(k-1)||isprime(k+1), print1(p, ", ")))} /* Klaus Brockhaus, Jun 05 2007 */
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CROSSREFS
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Cf. A127566.
Sequence in context: A095323 A100370 A095319 this_sequence A077500 A036955 A040179
Adjacent sequences: A129618 A129619 A129620 this_sequence A129622 A129623 A129624
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KEYWORD
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nonn
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AUTHOR
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J. M. Bergot (thekingfishb(AT)yahoo.ca), May 30 2007
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EXTENSIONS
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Edited and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 05 2007
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