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 A208011 #7 Jul 22 2025 21:06:20 %S A208011 19,361,1482,6084,16224,43264,92560,198025,369795,690561,1175034, %T A208011 1999396,3178672,5053504,7627464,11512449,16676595,24157225,33844690, %U A208011 47416996,64618224,88059456,117234312,156075049,203673379,265787809,340895730 %N A208011 Number of nX6 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 0 1 1 vertically. %C A208011 Column 6 of A208013 %H A208011 R. H. Hardin, <a href="/A208011/b208011.txt">Table of n, a(n) for n = 1..210</a> %F A208011 Empirical: a(n) = 2*a(n-1) +6*a(n-2) -14*a(n-3) -14*a(n-4) +42*a(n-5) +14*a(n-6) -70*a(n-7) +70*a(n-9) -14*a(n-10) -42*a(n-11) +14*a(n-12) +14*a(n-13) -6*a(n-14) -2*a(n-15) +a(n-16) %e A208011 Some solutions for n=4 %e A208011 ..1..1..1..1..0..0....0..0..1..0..0..1....1..0..0..1..0..0....1..0..0..1..0..0 %e A208011 ..0..1..1..1..1..1....0..0..1..1..1..1....0..0..1..1..1..1....0..1..1..0..0..1 %e A208011 ..1..0..0..1..0..0....0..0..1..0..0..1....1..0..0..1..0..0....1..0..0..1..0..0 %e A208011 ..0..1..0..0..1..0....0..0..1..0..0..1....0..0..1..0..0..1....0..0..1..0..0..1 %K A208011 nonn %O A208011 1,1 %A A208011 _R. H. Hardin_ Feb 22 2012