

A014091


Numbers that are the sum of 2 primes.


21



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

1,1


COMMENTS

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


LINKS



MAPLE

sort({seq(2+ithprime(j), j=1..21)} union {seq(2*k, k=2..ceil(ithprime(21)/2))}); # Emeric Deutsch, Jul 14 2004


MATHEMATICA

Take[ Union@ Flatten@ Table[ Prime@p + Prime@q, {p, 25}, {q, p}], 71] (* Robert G. Wilson v, Aug 31 2008 *)


PROG

(PARI) isA014091(n)= my(i, p); i=1; p=prime(i); while(p<n, if( isprime(np), 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 !! (n1)
a014091_list = filter (\x > any ((== 1) . a010051) $
map (x ) $ takeWhile (< x) a000040_list) [1..]


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



