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 A264013 #6 Nov 10 2015 10:50:26 %S A264013 1,5,169,20570,9150625,21860843125,252579343635025, %T A264013 12379056073433237760 %N A264013 Number of (n+1)X(n+1) arrays of permutations of 0..(n+1)^2-1 with each element having index change +-(.,.) 0,0 1,2 or 2,2. %C A264013 Diagonal of A264017. %e A264013 Some solutions for n=4 %e A264013 ..7..1.14..3..4....0..8.14..3..4....0..1..2..3..4...12..8.14..3..4 %e A264013 .12.13..0..8..9...17..6..7..1..9...12..6.19..8..9....5.18..0..1..9 %e A264013 .10.11.24..6..2...22.23.12.13..2...10.18.24.13.14...22.11.19.13..2 %e A264013 .15.23..5.18.19...15.16..5.18.19...15.23..5.11..7...15.23.17..6..7 %e A264013 .20.21.22.16.17...20.21.10.11.24...20.21.22.16.17...20.21.10.16.24 %Y A264013 Cf. A264017. %K A264013 nonn %O A264013 1,2 %A A264013 _R. H. Hardin_, Nov 01 2015