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A093706
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Primes p such that (pp'-1)/2 is prime, where p' denotes the next prime after p.
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1
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3, 5, 11, 29, 41, 71, 137, 281, 461, 599, 641, 787, 827, 881, 1091, 1129, 1301, 1409, 1607, 1627, 1951, 2129, 2267, 2357, 2381, 2557, 2687, 2887, 2917, 3469, 3527, 3557, 3581, 3967, 4127, 4229, 4337, 4547, 4889, 5009, 5309, 5741, 6131, 6133, 6247, 6343
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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MATHEMATICA
| Prime[ Select[ Range[850], PrimeQ[(Prime[ # ]Prime[ # + 1] - 1)/2] &]]
Transpose[Select[Partition[Prime[Range[900]], 2, 1], PrimeQ[ (Times@@#- 1)/2]&]][[1]] (* From Harvey P. Dale, Sep 17 2011 *)
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PROG
| (PARI) isA093706(n) = if(n<3, 0, isprime(n) && isprime((n*nextprime(n+1)-1)/2)) [From Michael Porter (michael_b_porter(AT)yahoo.com), Dec 15 2009]
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CROSSREFS
| Cf. A048797.
Sequence in context: A088357 A204857 A191025 * A109945 A045536 A019338
Adjacent sequences: A093703 A093704 A093705 * A093707 A093708 A093709
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 10 2004
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