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A141109
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Even numbers 2n such that for every prime p in [n,2n-2], 2n-p is also prime.
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1
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4, 6, 8, 10, 12, 14, 16, 18, 24, 30, 36, 42, 48, 60, 90, 210
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OFFSET
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1,1
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COMMENTS
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The Deshouillers et al. paper proves that 210 is the last term. This sequence is the same as 2*A002271, but why?
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LINKS
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Table of n, a(n) for n=1..16.
Jean-Marc Deshouillers, Andrew Granville, Wladyslaw Narkiewicz and Carl Pomerance, An upper bound in Goldbach's problem, Math. Comp. 61 (1993), 209-213.
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EXAMPLE
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30 is in this sequence because the primes p between 15 and 28 are {17,19,23} and 30-p is {13,11,7}.
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MATHEMATICA
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t={}; Do[If[And@@PrimeQ[2n-Prime[Range[PrimePi[n-1]+1, PrimePi[2n-2]]]], AppendTo[t, 2n]], {n, 2, 105}]; t
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CROSSREFS
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Sequence in context: A210939 A175246 A134928 * A186331 A061344 A066664
Adjacent sequences: A141106 A141107 A141108 * A141110 A141111 A141112
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KEYWORD
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fini,full,nonn
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AUTHOR
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T. D. Noe, Jun 03 2008
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STATUS
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approved
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