A202729 - OEIS

%I #6 Dec 18 2015 18:17:56

%S 1,1,2,12,304,44976,51871384,600608922384,87357442179208880,

%T 194354337721367202187520

%N Number of n X n nonnegative integer arrays with each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to n-1

%C Diagonal of A202735

%e Some solutions for n=4

%e ..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0

%e ..0..1..1..1....0..0..1..1....0..0..0..1....0..1..1..1....0..0..1..1

%e ..0..1..0..2....0..1..1..2....0..1..1..2....0..0..1..2....0..1..0..2

%e ..0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3....0..1..2..3

%K nonn

%O 1,3

%A _R. H. Hardin_ Dec 23 2011