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 A047182 #9 Jun 04 2013 12:11:17
%S A047182 0,0,0,3,4,14,20,55,83,209,329,791,1286,3002,5004,11439,19447,43757,
%T A047182 75581,167959,293929,646645,1144065,2496143,4457399,9657699,17383859,
%U A047182 37442159,67863914,145422674,265182524,565722719,1037158319
%N A047182 Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-2)/2.
%F A047182 a(n) = C(n, [(n-2)/2]) - 1 = A037955(n) - 1. - _Ralf Stephan_, Mar 16 2004
%K A047182 nonn
%O A047182 1,4
%A A047182 _Clark Kimberling_