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A164623
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Primes p such that p*(p-1)/2-5 and p*(p-1)/2+5 are also prime numbers.
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1
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13, 157, 673, 1069, 1117, 1153, 1213, 1597, 2029, 2089, 2437, 2713, 2833, 3613, 4057, 4909, 5653, 6337, 6529, 7549, 7993, 8053, 9613, 10789, 11497, 11689, 12073, 12373, 13309, 13669, 13789, 14173, 15289, 15937, 16249, 18097, 18637, 19249, 19993
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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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13 is in the sequence because 13*6-5=73 and 13*6+5=83 are both prime.
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MATHEMATICA
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Select[Prime[Range[2300]], PrimeQ[# (# - 1)/2 - 5] && PrimeQ[# (# - 1)/2 + 5] &]
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PROG
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(PARI) forprime(p=2, 10^6, my(b=binomial(p, 2)); if(isprime(b-5)&isprime(b+5), print1(p, ", "))); /* Joerg Arndt, Apr 10 2013 */
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CROSSREFS
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Cf. A008846, A020882, A068228, A068229, A082539, A086519, A107159, A158708, A139494, A164620, A164621, A164622, A023203.
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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Mathematica code adapted to the definition by Bruno Berselli, Apr 10 2013
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STATUS
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approved
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