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 A228733 #13 Sep 02 2013 11:52:38 %S A228733 2,4,8,16,28,50,88,156,278,496,886,1582,2824,5040,8994,16050,28642, %T A228733 51114,91218,162788,290512,518448,925222,1651150,2946640,5258570, %U A228733 9384438,16747458,29887496,53337194,95185500,169867942,303146148,540994292 %N A228733 Number of arrays of the median of three adjacent elements of some length n+2 0..1 array. %C A228733 Column 1 of A228740 %H A228733 R. H. Hardin, <a href="/A228733/b228733.txt">Table of n, a(n) for n = 1..210</a> %F A228733 Empirical: a(n) = 2*a(n-1) -a(n-3) +a(n-5). %F A228733 Empirical: G.f. -2*x*(1+x)*(x^2-x+1) / ( -1+2*x-x^3+x^5 ). - _R. J. Mathar_, Sep 02 2013 %e A228733 All solutions for n=4 %e A228733 ..1..1..0..0..1..1..1..0..0..1..0..0..1..1..0..0 %e A228733 ..0..1..0..0..0..1..0..1..1..1..0..1..1..0..1..0 %e A228733 ..1..1..1..1..0..1..0..1..0..0..0..0..0..1..1..0 %e A228733 ..1..1..1..0..1..0..0..0..0..0..1..1..1..0..1..0 %K A228733 nonn %O A228733 1,1 %A A228733 _R. H. Hardin_, Sep 01 2013