This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A232721 #10 Dec 05 2013 12:18:28
%S A232721 1,3,4,6,8,12,14,18,20,24,30,32,38,42,48,54,60,72,80,84,90,108,110,
%T A232721 132,138,140,150,180
%N A232721 Numbers not representable as the sum of two coprime nonprime numbers.
%C A232721 Numbers n such that A185279(n) = 0. 1 and 3 together with A141096.
%t A232721 t = Table[Length[Select[Range[n/2], ! PrimeQ[#] && ! PrimeQ[n - #] && GCD[#, n - #] == 1 &]], {n, 2000}]; Flatten[Position[t, 0]] (* _T. D. Noe_, Dec 05 2013 *)
%Y A232721 Cf. A062303, A018252, A141095, A141098.
%K A232721 nonn,full,fini
%O A232721 1,2
%A A232721 _Irina Gerasimova_, Nov 28 2013