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A124065
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Numbers k such that 8*k - 1 and 8*k + 1 are twin primes.
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9
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9, 24, 30, 39, 54, 75, 129, 144, 165, 186, 201, 234, 261, 264, 324, 336, 339, 375, 390, 396, 420, 441, 459, 471, 516, 534, 600, 621, 654, 660, 690, 705, 735, 795, 819, 849, 870, 891, 936, 945, 1011, 1029, 1125, 1155, 1179, 1215, 1221, 1251, 1284, 1395, 1419
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OFFSET
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1,1
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LINKS
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EXAMPLE
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9 is in the sequence since 8*9 - 1 = 71 and 8*9 + 1 = 73 are twin primes.
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MATHEMATICA
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Select[Range[1500], And @@ PrimeQ[{-1, 1} + 8# ] &] (* Ray Chandler, Nov 16 2006 *)
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PROG
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(Magma) [n: n in [1..2000] | IsPrime(8*n+1) and IsPrime(8*n-1)] // Vincenzo Librandi, Mar 08 2010
(Python)
from sympy import isprime
def ok(n): return isprime(8*n - 1) and isprime(8*n + 1)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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