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 A172233 #6 Mar 30 2012 18:41:21 %S A172233 0,1,2,3,4,5,6,8,9,10,11,12,13,16,18,20,21,22,24,25,26,27,29,32,36,40, %T A172233 42,44,45,48,50,52,53,54,57,58,59,61,64,72,80,84,88,90,93,96,100,104, %U A172233 106,108,109,114,116,117,118,121,122,123,125,128,144,160 %N A172233 Positive numbers of form 2^m - 2^l - 3*2^k, m>l>k>=0. %e A172233 2^7 - 2^5 - 3*2^2 = 128-32-12 = 84, so 84 is in sequence. %o A172233 (PARI) v=vector(10000);k=1;for(v2=2,50,for(v1=1,v2-1,for(v0=0,v1-1,t=2^v2-3*2^v0-2^v1;v[k++]=t)));vecsort(v) %Y A172233 Cf. A023758. %K A172233 nonn %O A172233 1,3 %A A172233 _Ralf Stephan_, Nov 20 2010