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 A207555 #7 Jul 22 2025 20:34:50 %S A207555 1791,3207681,3323115736,3168082336959,3054158366460488, %T A207555 2964756265273648883,2876868686935789680075,2790347210410991592878863, %U A207555 2705587415313932036439553600,2623332913249978851468865268215 %N A207555 Number of 7Xn 0..2 arrays avoiding the pattern z-2 z-1 z in any row, column, nw-to-se diagonal or ne-to-sw antidiagonal. %C A207555 Row 7 of A207550 %H A207555 R. H. Hardin, <a href="/A207555/b207555.txt">Table of n, a(n) for n = 1..28</a> %e A207555 Some solutions for n=4 %e A207555 ..0..2..2..1....2..1..0..2....0..2..2..2....0..1..1..2....0..2..0..2 %e A207555 ..1..2..2..1....1..2..2..1....1..1..0..2....0..1..0..1....2..2..0..2 %e A207555 ..0..0..1..1....1..0..1..1....0..0..1..0....2..2..0..0....2..0..1..0 %e A207555 ..2..1..1..0....0..0..2..0....1..2..0..2....0..2..2..0....0..2..1..0 %e A207555 ..1..0..0..1....0..2..0..0....1..0..2..0....0..1..0..1....2..1..2..1 %e A207555 ..1..2..0..0....0..1..0..0....1..0..0..0....1..2..0..0....2..2..1..0 %e A207555 ..2..2..1..2....1..2..0..0....2..1..0..0....1..2..2..2....0..2..2..2 %K A207555 nonn %O A207555 1,1 %A A207555 _R. H. Hardin_ Feb 18 2012