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 A264543 #4 Nov 17 2015 15:31:36 %S A264543 0,2,16,216,14852,1994830,591482528,510948245264,1135318355003028, %T A264543 6257173857277450930 %N A264543 Number of (n+1)X(n+1) arrays of permutations of 0..(n+1)^2-1 with each element having directed index change -1,1 -1,2 1,0 or 0,-1. %C A264543 Diagonal of A264550. %e A264543 Some solutions for n=4 %e A264543 ..1..5..6..4..8....1..5..3..4..7....1..2..3..4..7....1..2..3..4..7 %e A264543 ..0..7..2..3.12....0.10..2..9.12....0.10..8..9.12....0.10..8.11.12 %e A264543 .11.15.16.14..9...11..6.13..8.17....5..6.13.14.18....5..6.13.17..9 %e A264543 .10.20.18.13.23...16.20.18.21.14...16.11.20.21.23...16.20.18.21.14 %e A264543 .21.22.17.24.19...15.22.23.24.19...15.22.17.24.19...15.22.23.24.19 %Y A264543 Cf. A264550. %K A264543 nonn %O A264543 1,2 %A A264543 _R. H. Hardin_, Nov 17 2015