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 A221260 #5 Jun 02 2025 08:13:56 %S A221260 0,1024,1560,44903401,4684821704,4919350997521,1286684357154700, %T A221260 711683286892712289,249788326721013262468,113635514869793774013025, %U A221260 44202928096066452637659216 %N A221260 Number of 6Xn arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2. %C A221260 Row 6 of A221255 %e A221260 Some solutions for n=3 %e A221260 ..0..2..2....1..2..0....1..2..0....1..2..0....0..2..1....0..2..1....0..2..1 %e A221260 ..0..2..1....1..2..0....0..2..0....0..2..0....0..2..2....0..2..0....0..2..0 %e A221260 ..0..2..1....0..2..0....1..2..2....2..2..0....0..2..1....2..2..0....1..2..0 %e A221260 ..0..2..0....1..2..1....0..2..0....0..2..1....0..2..1....1..2..0....1..2..1 %e A221260 ..0..2..0....1..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..0 %e A221260 ..2..2..0....0..2..1....0..2..1....0..2..1....1..2..0....2..2..0....1..2..1 %K A221260 nonn %O A221260 1,2 %A A221260 _R. H. Hardin_ Jan 06 2013