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A216498
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Primes p with property that there exists a number d>0 such that numbers p-k*d, k=1...5, are five primes.
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7
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157, 257, 311, 353, 463, 509, 691, 757, 823, 839, 881, 907, 941, 953, 1063, 1097, 1223, 1229, 1249, 1297, 1301, 1307, 1439, 1459, 1531, 1583, 1669, 1723, 1777, 1879, 1907, 1913, 1931, 2027, 2087, 2089, 2141, 2143, 2179, 2207, 2293, 2351, 2371, 2377, 2399, 2411
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OFFSET
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1,1
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COMMENTS
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Conjecture: only 9198 primes are not in the sequence: 2, 3, ..., 2521081.
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LINKS
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EXAMPLE
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157 is in the sequence because with d=30: 127, 97, 67, 37, 7 are all primes.
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MATHEMATICA
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prms = 5; fQ[p_] := Module[{d = 1}, While[prms*d < p && Union[PrimeQ[p - Range[prms]*d]] != {True}, d++]; prms*d < p]; Select[Prime[Range[2, PrimePi[2411]]], fQ] (* T. D. Noe, Sep 08 2012 *)
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PROG
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(PARI) is(n)=my(t); forprime(p=2, n-16, if((n-p)%5==0 && isprime((t=(n-p)/5)+p) && isprime(2*t+p) && isprime(3*t+p) && isprime(4*t+p) && isprime(n), return(1))); 0 \\ Charles R Greathouse IV, Sep 10 2014
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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