login
Number of (n+1)X(2+1) 0..2 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction
1

%I #4 Nov 23 2014 12:35:36

%S 217,2029,17024,141857,1155519,9376751,75647740,609534839,4903892459,

%T 39438538201,317050695780,2548528796645,20483568025431,

%U 164629748544475,1323120367104228,10633755035857083,85461577059693963,686837682555429189

%N Number of (n+1)X(2+1) 0..2 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction

%C Column 2 of A250454

%H R. H. Hardin, <a href="/A250448/b250448.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) +6*a(n-2) -210*a(n-3) +173*a(n-4) +976*a(n-5) -674*a(n-6) -1632*a(n-7) +800*a(n-8) +1128*a(n-9) -288*a(n-10) -288*a(n-11)

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 23 2014