cp's OEIS Frontend

A250522 Number of (n+1)X(3+1) 0..2 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.

%I A250522 #7 Nov 14 2018 14:05:37
%S A250522 867,5029,21955,82023,279161,896191,2771901,8374485,24944039,73714737,
%T A250522 217061167,638657339,1880873517,5549684027,16412416857,48651910233,
%U A250522 144539853387,430255351197,1282888681851,3830445412591,11449627377217
%N A250522 Number of (n+1)X(3+1) 0..2 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 A250522 R. H. Hardin, <a href="/A250522/b250522.txt">Table of n, a(n) for n = 1..210</a>
%F A250522 Empirical: a(n) = 14*a(n-1) - 85*a(n-2) + 294*a(n-3) - 639*a(n-4) + 906*a(n-5) - 839*a(n-6) + 490*a(n-7) - 164*a(n-8) + 24*a(n-9).
%F A250522 Empirical g.f.: x*(867 - 7109*x + 25244*x^2 - 52780*x^3 + 72501*x^4 - 66849*x^5 + 39534*x^6 - 13260*x^7 + 1944*x^8) / ((1 - x)^5*(1 - 2*x)^3*(1 - 3*x)). - _Colin Barker_, Nov 14 2018
%e A250522 Some solutions for n=4:
%e A250522 ..2..2..2..1....2..2..0..0....2..1..1..0....0..0..0..0....1..0..1..0
%e A250522 ..1..1..2..1....2..2..0..1....2..1..1..1....0..0..0..0....2..1..2..2
%e A250522 ..1..1..2..1....2..2..0..1....0..0..0..0....0..0..0..0....2..1..2..2
%e A250522 ..0..0..2..1....2..2..1..2....1..1..1..1....1..2..2..2....0..0..1..1
%e A250522 ..0..0..2..1....1..1..1..2....0..0..2..2....0..1..1..1....0..0..1..1
%Y A250522 Column 3 of A250527.
%K A250522 nonn
%O A250522 1,1
%A A250522 _R. H. Hardin_, Nov 24 2014