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Composite numbers which can be represented as the sum of two primes (i.e., A002808 excluding A025583).
2

%I #15 Aug 03 2017 01:02:46

%S 4,6,8,9,10,12,14,15,16,18,20,21,22,24,25,26,28,30,32,33,34,36,38,39,

%T 40,42,44,45,46,48,49,50,52,54,55,56,58,60,62,63,64,66,68,69,70,72,74,

%U 75,76,78,80,81,82,84,85,86,88,90,91,92,94,96,98,99,100,102,104,105

%N Composite numbers which can be represented as the sum of two primes (i.e., A002808 excluding A025583).

%H Reinhard Zumkeller, <a href="/A051035/b051035.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PrimePartition.html">Prime Partition.</a>

%t r[n_] := Reduce[2 <= p <= q && n == p + q, {p, q}, Primes]; Select[Range[4, 105], r[#] =!= False && ! PrimeQ[#] & ] (* _Jean-François Alcover_, Oct 29 2012 *)

%o (Haskell)

%o a051035 n = a051035_list !! (n-1)

%o a051035_list = filter ((== 0) . a010051) a014091_list

%Y Cf. A002808, A025583.

%Y Cf. A010051, subsequence of A014092.

%K nonn

%O 1,1

%A _Eric W. Weisstein_