cp's OEIS Frontend

A212924 Number of n X n 0..n-1 arrays with no column j greater than column j-1 in all rows.

%I A212924 #12 Aug 08 2025 16:16:27
%S A212924 1,15,18226,4041974015,285912852294921876,
%T A212924 10046278068363977051128904352,
%U A212924 252848108054080530934326716965286554552380,6218295117529777826597449794390561827118547543121719263231,195564579665280381327483744593329391511083800439826359765867240005114671403240
%N A212924 Number of n X n 0..n-1 arrays with no column j greater than column j-1 in all rows.
%H A212924 R. H. Hardin, <a href="/A212924/b212924.txt">Table of n, a(n) for n = 1..13</a>
%e A212924 Some solutions for n=3:
%e A212924 ..0..0..1....2..2..0....0..1..2....1..0..1....1..1..1....2..1..2....1..2..1
%e A212924 ..1..2..0....1..2..0....1..2..0....1..2..2....1..0..1....1..2..2....2..1..2
%e A212924 ..1..2..1....2..1..0....0..0..0....2..1..2....2..1..2....1..2..0....1..0..2
%Y A212924 Diagonal of A212930.
%K A212924 nonn
%O A212924 1,2
%A A212924 _R. H. Hardin_, May 31 2012