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 A263423 #3 Oct 17 2015 15:53:08 %S A263423 6,961,532620,141086884,34502512032,9414955824400,2581177525941432, %T A263423 696932281399739401,188117459428481322624,50895976667736734492176, %U A263423 13771969942166582196102000,3725144577531136163481836521 %N A263423 Number of nX5 arrays of permutations of 0..n*5-1 with each element moved a city block distance of 0 or 2. %C A263423 Column 5 of A263424. %e A263423 Some solutions for n=2 %e A263423 ..6..1..4..3..8....0..7..4..3..2....0..7..6..9..4....0..3..2..1..4 %e A263423 ..5..0..9..2..7....1..8..5..6..9....5..2..1..8..3....7..6..5..8..9 %Y A263423 Cf. A263424. %K A263423 nonn %O A263423 1,1 %A A263423 _R. H. Hardin_, Oct 17 2015