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A172056
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Primes p such that 2*p+-1 and 2*p+-3 are all composites.
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1
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59, 61, 103, 109, 149, 151, 163, 257, 313, 389, 401, 449, 479, 541, 569, 571, 673, 677, 709, 733, 769, 821, 823, 839, 857, 883, 919, 947, 971, 983, 1061, 1087, 1093, 1097, 1129, 1151, 1163, 1181, 1249, 1283, 1301, 1319, 1321, 1381, 1433, 1489, 1493, 1549
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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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a(1)=59 because 2*59-1=117, 2*59+1=119, 2*59-3=115, 2*59+3=121 are all composites.
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MATHEMATICA
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okQ[n_]:=Union[PrimeQ[{2n+1, 2n-1, 2n+3, 2n-3}]]=={False}; Select[Prime[Range[250]], okQ] (* Harvey P. Dale, Feb 07 2010 *)
Select[Prime[Range[300]], AllTrue[2#+{1, 3, -1, -3}, CompositeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 20 2015 *)
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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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