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 A266207 #5 Aug 12 2016 07:04:21 %S A266207 0,0,0,8,544,20976,3124800,269723136,61919980032,9210279970560, %T A266207 2897383466019840 %N A266207 Number of nX2 arrays containing 2 copies of 0..n-1 with no element plus any horizontal, vertical, diagonal or antidiagonal neighbor equal to n-1. %C A266207 Column 2 of A266208. %e A266207 Some solutions for n=6 %e A266207 ..0..2....2..0....2..1....0..2....2..1....2..4....5..3....5..4....1..2....3..0 %e A266207 ..1..1....2..4....0..0....0..1....2..0....0..2....4..3....3..5....0..0....4..4 %e A266207 ..3..0....0..4....4..4....1..3....4..4....4..0....4..0....3..1....4..2....2..5 %e A266207 ..3..4....3..3....3..3....3..5....5..5....3..3....2..0....0..1....5..4....2..5 %e A266207 ..4..5....5..5....5..5....4..5....3..1....5..1....2..1....0..2....3..3....1..1 %e A266207 ..2..5....1..1....2..1....2..4....0..3....1..5....5..1....2..4....5..1....0..3 %Y A266207 Cf. A266208. %K A266207 nonn %O A266207 1,4 %A A266207 _R. H. Hardin_, Dec 23 2015