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A174874
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Smaller prime number of two distinct primes a and b such that a*b+-d are primes, and d is a difference between a and b.
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2
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5, 7, 13, 41, 61, 73, 139, 181, 193, 229, 241, 349, 389, 409, 433, 457, 463, 569, 577, 661, 673, 709, 769, 881, 1021, 1049, 1117, 1201, 1249, 1321, 1801, 1873, 2029, 2089, 2113, 2281, 2389, 2473, 2521, 2593, 2689, 2857, 3109, 3169, 3181, 3301, 3313, 3361
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OFFSET
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1,1
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COMMENTS
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2*3=6;3-2=1;6-1=5, 2*5=10;5-2=3;10-3=7, 3*5=15;5-3=2;15-2=13,..
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LINKS
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Table of n, a(n) for n=1..48.
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MATHEMATICA
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lst={}; Do[pa=Prime[a]; Do[pb=Prime[b]; sp=pa*pb; dp=Abs[pa-pb]; If[PrimeQ[sp-dp]&&PrimeQ[sp+dp], AppendTo[lst, sp-dp]], {b, a+1, 5!}], {a, 5!}]; Union@lst
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CROSSREFS
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Cf. A088708, A174872, A174873
Sequence in context: A018464 A063446 A064600 * A109904 A077781 A102872
Adjacent sequences: A174871 A174872 A174873 * A174875 A174876 A174877
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KEYWORD
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nonn
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AUTHOR
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Vladimir Joseph Stephan Orlovsky, Mar 31 2010
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STATUS
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approved
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