|
%I #8 Nov 22 2018 11:33:38
%S 2306,11644,55386,250964,1097986,4685964,19649066,81358084,333810066,
%T 1360557884,5518553146,22303914804,89906240546,361699655404,
%U 1453028599626,5830816129124,23379393301426,93686006746524
%N Number of (n+1) X (5+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction.
%H R. H. Hardin, <a href="/A250874/b250874.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4); a(n) = (4112*4^n - 3915*3^n + 1080*2^n + 55)/3.
%F Empirical g.f.: 2*x*(1153 - 5708*x + 9828*x^2 - 5328*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)). - _Colin Barker_, Nov 22 2018
%e Some solutions for n=3:
%e ..2..2..2..2..2..2....2..2..2..2..2..2....3..3..3..3..3..3....2..2..2..2..2..1
%e ..1..1..1..1..1..1....0..0..0..2..2..2....1..2..3..3..3..3....1..1..1..1..1..2
%e ..0..0..0..0..0..0....1..1..1..3..3..3....1..2..3..3..3..3....0..0..0..0..0..1
%e ..0..0..1..1..1..2....0..0..0..2..3..3....0..2..3..3..3..3....0..0..0..0..2..3
%Y Column 5 of A250877.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 28 2014
| 