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 A207087 #7 Jul 22 2025 20:00:49 %S A207087 81,6561,248525,8244759,243794389,6897033117,189659424011, %T A207087 5142718466575,138294979168509,3702335938084439,98860585328779343, %U A207087 2635998227067669263,70227731343750962247,1870120121498081593459,49786813201495602614131 %N A207087 Number of nX7 0..1 arrays avoiding 0 0 0 horizontally and 0 0 1 vertically. %C A207087 Column 7 of A207088 %H A207087 R. H. Hardin, <a href="/A207087/b207087.txt">Table of n, a(n) for n = 1..210</a> %e A207087 Some solutions for n=4 %e A207087 ..1..0..1..0..1..0..1....1..1..0..0..1..1..1....0..0..1..0..1..1..1 %e A207087 ..0..0..1..0..0..1..0....1..1..1..1..1..0..1....1..1..1..1..0..0..1 %e A207087 ..0..0..1..0..1..0..1....0..0..1..1..0..1..1....0..1..1..0..1..0..0 %e A207087 ..0..0..1..0..0..1..0....0..0..1..0..0..1..1....1..0..1..1..1..0..0 %K A207087 nonn %O A207087 1,1 %A A207087 _R. H. Hardin_ Feb 15 2012