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A014091
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Numbers that are the sum of 2 primes.
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21
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4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 28, 30, 31, 32, 33, 34, 36, 38, 39, 40, 42, 43, 44, 45, 46, 48, 49, 50, 52, 54, 55, 56, 58, 60, 61, 62, 63, 64, 66, 68, 69, 70, 72, 73, 74, 75, 76, 78, 80, 81, 82, 84, 85, 86, 88, 90, 91, 92, 94, 96, 98
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OFFSET
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1,1
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COMMENTS
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Sequence consists of all primes + 2 and, conjecturally (Goldbach), of all even integers larger than 2. The Goldbach conjecture is that every even number is the sum of two primes. - Emeric Deutsch, Jul 14 2004
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LINKS
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MAPLE
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sort({seq(2+ithprime(j), j=1..21)} union {seq(2*k, k=2..ceil(ithprime(21)/2))}); # Emeric Deutsch, Jul 14 2004
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MATHEMATICA
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Take[ Union@ Flatten@ Table[ Prime@p + Prime@q, {p, 25}, {q, p}], 71] (* Robert G. Wilson v, Aug 31 2008 *)
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PROG
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(PARI) isA014091(n)= my(i, p); i=1; p=prime(i); while(p<n, if( isprime(n-p), return(1)); i++; p=prime(i)); 0
n=0; for(a=2, 100, if(isA014091(a), print(n, " ", a); n++)) \\ R. J. Mathar, Aug 20 2006
(Haskell)
a014091 n = a014091_list !! (n-1)
a014091_list = filter (\x -> any ((== 1) . a010051) $
map (x -) $ takeWhile (< x) a000040_list) [1..]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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