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 A141592 Numbers k such that k, k + 210*1, k + 210*2, k + 210*3, k + 210*4 are averages of pairs of twin primes. 0
 1308498, 3042492, 3042702, 7445310, 20031102, 31572522, 44687988, 54266292, 141208620, 182316522, 237416370, 357080022, 448436322, 611641188, 699458412, 761126028, 774997368, 794065968, 836452962, 915215592, 944958942, 1009194618, 1581935940, 1763255562, 1871007372 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..25. EXAMPLE 1308498 and 1308708, 1308918, 1309128, 1309338 are averages of twin primes. 3042492 and 3042702, 3042912, 3043122, 3043332 are averages of twin primes. MATHEMATICA q=210; lst={}; Do[If[PrimeQ[n-1]&&PrimeQ[n+1]&&PrimeQ[n+q*1-1]&& PrimeQ[n+q*1+1]&& PrimeQ[n+q*2-1]&&PrimeQ[n+q*2+1]&& PrimeQ[n+q*3-1]&& PrimeQ[n+q*3+1]&& PrimeQ[n+q*4-1]&&PrimeQ[n+q*4+1], AppendTo[lst, n]], {n, 10^8}]; lst Select[Range[55*10^6], AllTrue[{#-1, #+1, #+209, #+211, #+419, #+421, #+629, #+631, #+839, #+841}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Aug 08 2017 *) PROG (Magma) [k:k in [1..55000000]|forall{m:m in [0, 210, 420, 630, 840]|IsPrime(k+m-1) and IsPrime(k+m+1)}]; // Marius A. Burtea, Jan 13 2020 CROSSREFS Cf. A001097, A001359, A006512, A014574. Sequence in context: A186138 A066702 A261731 * A234710 A116495 A179584 Adjacent sequences: A141589 A141590 A141591 * A141593 A141594 A141595 KEYWORD nonn AUTHOR Vladimir Joseph Stephan Orlovsky, Aug 20 2008 EXTENSIONS Edited by N. J. A. Sloane, Aug 24 2008 a(9)-a(25) from Amiram Eldar, Jan 13 2020 STATUS approved

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Last modified July 12 12:19 EDT 2024. Contains 374247 sequences. (Running on oeis4.)