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 A207776 #7 Jul 22 2025 20:50:01 %S A207776 21,441,972,7164,43264,195160,1246206,7381202,35627804,220514498, %T A207776 1274712127,6417933773,38976638418,221650017452,1149943284883, %U A207776 6878942092623,38712906007620,205352839927648,1212860472464769 %N A207776 Number of 6Xn 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 0 vertically. %C A207776 Row 6 of A207774 %H A207776 R. H. Hardin, <a href="/A207776/b207776.txt">Table of n, a(n) for n = 1..210</a> %e A207776 Some solutions for n=4 %e A207776 ..0..0..1..1....0..1..1..0....0..1..0..1....0..0..1..0....1..0..0..1 %e A207776 ..1..1..0..0....1..1..0..0....1..0..0..1....1..0..1..0....1..1..0..1 %e A207776 ..1..1..0..0....1..1..0..0....1..1..0..1....1..0..1..0....1..1..0..0 %e A207776 ..0..1..0..0....0..1..0..0....1..1..0..1....0..0..1..0....0..1..0..1 %e A207776 ..0..1..0..0....1..1..0..0....1..1..0..1....0..0..1..0....1..0..0..1 %e A207776 ..0..1..0..0....1..1..0..0....0..1..0..0....0..0..1..0....1..0..0..1 %K A207776 nonn %O A207776 1,1 %A A207776 _R. H. Hardin_ Feb 20 2012