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 A089828 #3 Mar 30 2012 18:50:42
%S A089828 0,0,0,0,8,16,48,96,192,384,768,1536,4352,8704,17408,34816,69632,
%T A089828 139264,339968,679936,1359872,2719744,5439488,10878976,21757952,
%U A089828 43515904,87031808,174063616,348127232,696254464,1581252608
%N A089828 Number of subsets of {1,.., n} containing at least one twin prime pair.
%C A089828 a(n) = A000079(n)-A089827(n).
%Y A089828 Cf. A071538, A001359, A006512.
%K A089828 nonn
%O A089828 1,5
%A A089828 _Reinhard Zumkeller_, Nov 12 2003