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 A221629 #6 Jul 23 2025 02:04:27 %S A221629 1,8,29124,183919920,15258126049410,2638115823321645192, %T A221629 2031241364747667201263520,3210318128660193294063849550080, %U A221629 13896214616394139128043246845049514250 %N A221629 Number of 7Xn arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row. %C A221629 Row 7 of A221623 %H A221629 R. H. Hardin, <a href="/A221629/b221629.txt">Table of n, a(n) for n = 1..12</a> %e A221629 Some solutions for n=3 %e A221629 ..1..2..3....1..2..3....2..3..1....3..1..2....1..3..2....3..1..2....1..3..2 %e A221629 ..2..3..1....1..3..2....1..3..2....1..3..2....2..1..3....2..3..1....2..1..3 %e A221629 ..3..1..2....2..1..3....2..1..3....2..3..1....2..3..1....2..3..1....2..1..3 %e A221629 ..3..1..2....1..3..2....3..1..2....2..1..3....2..1..3....3..1..2....1..3..2 %e A221629 ..2..1..3....2..3..1....2..1..3....2..1..3....1..3..2....1..3..2....2..3..1 %e A221629 ..2..3..1....3..1..2....1..3..2....1..3..2....3..1..2....2..1..3....2..3..1 %e A221629 ..2..1..3....1..3..2....2..3..1....3..1..2....2..1..3....2..3..1....2..1..3 %K A221629 nonn %O A221629 1,2 %A A221629 _R. H. Hardin_ Jan 21 2013