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%I #6 Sep 19 2017 03:46:40
%S 0,1,27,35,51,57,65,77,87,93,95,117,119,121,123,125,135,143,145,147,
%T 155,161,171,177,185,187,189,203,205,207,209,215,217,219,221,237,245,
%U 247,249,255,261,267,275,287,289,291,297,299,301,303,305,321,323,325,327
%N Nonprime numbers that are not a sum of 2 primes.
%H G. C. Greubel, <a href="/A164376/b164376.txt">Table of n, a(n) for n = 1..1000</a>
%F Equals {0,1} union A025583.
%t f[n_] := (p = 0; pn = PrimePi[n]; Do[If[n == Prime[i] + Prime[k], p = p + 1; If[p > 2, Break[]]], {i, 1, pn}, {k, i, pn}]; p); Join[{0, 1}, Select[Range[2, 6000], ! PrimeQ[#] && f[#] == 0 &]] (* _G. C. Greubel_, Sep 18 2017 *)
%Y Cf. A025583, A141468.
%K nonn
%O 1,3
%A _Juri-Stepan Gerasimov_, Aug 14 2009
%E Comment turned into formula by _R. J. Mathar_, Aug 20 2009