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Number of (n+1) X 2 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.
1

%I #8 Jun 06 2018 05:05:23

%S 32,121,447,1579,5352,17559,56219,176797,548760,1687165,5151519,

%T 15651063,47379056,143054539,431129547,1297582777,3901661040,

%U 11723857281,35211417503,105718138339,317330575512,952360824991,2857854226587

%N Number of (n+1) X 2 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.

%C Column 1 of A203965.

%H R. H. Hardin, <a href="/A203958/b203958.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) -40*a(n-2) +82*a(n-3) -91*a(n-4) +52*a(n-5) -12*a(n-6).

%F Empirical g.f.: x*(32 - 199*x + 517*x^2 - 675*x^3 + 432*x^4 - 108*x^5) / ((1 - x)^3*(1 - 2*x)^2*(1 - 3*x)). - _Colin Barker_, Jun 06 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A203965.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 08 2012