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 A181765 #17 Apr 04 2014 13:19:31
%S A181765 0,2,12,54,230,948,3860,15624,63014,253588,1019072,4091174,16412668,
%T A181765 65808044,263755984,1056789662,4233176854,16953418148,67885557896,
%U A181765 271793651816,1088059997732,4355377285932,17432688395816,69770793302408,279227252601884
%N A181765 Number of subsets of the interval [-n .. +n] with sums > 0.
%C A181765 a(n) = A000302(n) - A047653(n) = (A004171(n) - A000980(n)) / 2.
%H A181765 Ray Chandler, <a href="/A181765/b181765.txt">Table of n, a(n) for n = 0..1660</a> (terms < 10^1000)
%e A181765 a(1) = #{{0,1}, {1}} = 2;
%e A181765 a(2) = #{{-2,0,1,2}, {-2,1,2}, {-1,0,1,2}, {-1,0,2}, {-1,1,2}, {-1,2}, {0,1}, {0,1,2}, {0,2}, {1}, {1,2}, {2}} = 12.
%o A181765 (Haskell)
%o A181765 import Data.List (subsequences)
%o A181765 a181765 n = length [xs | xs <- subsequences [-n..n], sum xs > 0]
%o A181765 -- _Reinhard Zumkeller_, Feb 22 2012, Nov 13 2010
%K A181765 nonn
%O A181765 0,2
%A A181765 _Reinhard Zumkeller_