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Search: id:A025017
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| A025017 |
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a(p) = least 2k such that p is the least prime in a Goldbach partition of 2k, where p = prime(n). |
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+0
7
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| 4, 6, 12, 30, 124, 122, 418, 98, 220, 346, 308, 1274, 1144, 962, 556, 2512, 3526, 1382, 1856, 4618, 992, 3818, 7432, 12778, 5978, 26098, 2642, 23266, 10268, 19696, 6008, 34192, 22606, 5372, 37768, 13562, 9596, 22832, 59914, 7426, 88786, 50312, 97768
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Minimal integer m such that m=p(n)+q=sum of 2 primes, where p(n)<=q is the n-th prime and there is no prime r<p(n) such that m-r is prime. - Robin Garcia (verob99(AT)teleline.es), Feb 12 2005
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LINKS
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N. J. A. Sloane, Table of n, a(n) for n=1..977 (from the web page of Tomas Oliveira e Silva)
Tomas Oliveira e Silva, Goldbach conjecture verification
Index entries for sequences related to Goldbach conjecture
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EXAMPLE
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a(4)=30=7+23 because p(4)=7, q=23 is prime and there is no prime r<p(4)=7 such that a(4)-r is prime.
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PROGRAM
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(Matlab) p1 = primes(1000000); d(1, :) = p1; d(2, :) = d(1, :) - d(1, :); i = 4; k = 1; n = 0; while i <= 5000000 while not(isprime(i - d(1, k))) k = k + 1; end; if d(2, k) == 0 d(2, k) = i; if k == n + 1 while d(2, n+1) > 0 n = n + 1; end; if n > 0 d(2, 1:n) end; end; end; k = 1; i = i + 2; end; - Lei Zhou (lzhou5(AT)emory.edu), Jan 26 2005
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CROSSREFS
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For records see A133427, A133428.
Sequence in context: A056495 A025018 A102043 this_sequence A133427 A027070 A087785
Adjacent sequences: A025014 A025015 A025016 this_sequence A025018 A025019 A025020
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KEYWORD
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nonn
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AUTHOR
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David W. Wilson (davidwwilson(AT)comcast.net)
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), May 05 2007; b-file added Nov 27 2007
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