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 A207549 #7 Jul 22 2025 20:34:21 %S A207549 1791,3207681,3434478282,3444706587880,3281119335987704, %T A207549 3082694275519480041,2876868686935789680075,2678620674955838194068380, %U A207549 2491610702126355619980595983,2316819788394652271932508770307 %N A207549 Number of nX7 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 A207549 Column 7 of A207550 %H A207549 R. H. Hardin, <a href="/A207549/b207549.txt">Table of n, a(n) for n = 1..124</a> %e A207549 Some solutions for n=4 %e A207549 ..1..1..0..2..2..0..2....1..1..0..2..1..1..2....2..1..1..0..0..0..1 %e A207549 ..0..1..1..1..2..0..1....1..1..0..1..0..0..1....1..2..0..0..2..1..2 %e A207549 ..0..1..0..1..1..2..2....0..1..0..0..0..2..2....0..2..1..2..0..0..0 %e A207549 ..2..2..0..1..0..1..0....1..1..1..2..2..2..0....2..1..1..0..0..0..0 %K A207549 nonn %O A207549 1,1 %A A207549 _R. H. Hardin_ Feb 18 2012