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A085637
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Numbers k such that k*prime(k) -+ 1 are twin primes.
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3
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2, 30, 72, 144, 312, 336, 510, 690, 990, 1122, 1254, 1272, 1410, 2082, 2376, 2508, 2586, 2664, 2802, 3060, 3096, 3180, 3432, 3510, 3684, 4062, 4506, 5526, 5790, 6174, 7224, 8064, 8388, 9078, 9390, 9504, 10698, 10794, 10884, 10992, 11046, 11334
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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k=30 is a term because 30*prime(30) +- 1 = 3390 +- 1 are twin primes.
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MATHEMATICA
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Select[Range[15000], PrimeQ[ # Prime[ # ] - 1] && PrimeQ[ # Prime[ # ] + 1] &]
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PROG
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(Magma) [n: n in [1..11500] | IsPrime(n*NthPrime(n) - 1) and IsPrime(n*NthPrime(n) + 1) ]; // Vincenzo Librandi, Oct 05 2012
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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