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 A141109 Even numbers 2n such that for every prime p in [n,2n-2], 2n-p is also prime. 1
 4, 6, 8, 10, 12, 14, 16, 18, 24, 30, 36, 42, 48, 60, 90, 210 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The Deshouillers et al. paper proves that 210 is the last term. This sequence is the same as 2*A002271, but why? LINKS 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. EXAMPLE 30 is in this sequence because the primes p between 15 and 28 are {17,19,23} and 30-p is {13,11,7}. MATHEMATICA t={}; Do[If[And@@PrimeQ[2n-Prime[Range[PrimePi[n-1]+1, PrimePi[2n-2]]]], AppendTo[t, 2n]], {n, 2, 105}]; t CROSSREFS Sequence in context: A353537 A134928 A279040 * A333197 A289426 A186331 Adjacent sequences: A141106 A141107 A141108 * A141110 A141111 A141112 KEYWORD fini,full,nonn AUTHOR T. D. Noe, Jun 03 2008 STATUS approved

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Last modified May 24 23:50 EDT 2024. Contains 372782 sequences. (Running on oeis4.)