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Number of (n+1)X2 0..5 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) nondecreasing in column and row directions, respectively
1

%I #5 Mar 31 2012 12:37:00

%S 406,4471,36672,269254,1769897,10808414,62091544,339988204,1789320301,

%T 9113698989,45160825978,218642188474,1037767632628,4842691334069,

%U 22269571121734,101118099777276,454107943970246,2019835994942138

%N Number of (n+1)X2 0..5 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) nondecreasing in column and row directions, respectively

%C Column 1 of A203944

%H R. H. Hardin, <a href="/A203937/b203937.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 21*a(n-1) -175*a(n-2) +665*a(n-3) -518*a(n-4) -4718*a(n-5) +14499*a(n-6) +2188*a(n-7) -72674*a(n-8) +72643*a(n-9) +176058*a(n-10) -334377*a(n-11) -217839*a(n-12) +793068*a(n-13) +52794*a(n-14) -1221588*a(n-15) +286044*a(n-16) +1323862*a(n-17) -558111*a(n-18) -1048265*a(n-19) +578773*a(n-20) +617787*a(n-21) -401569*a(n-22) -272713*a(n-23) +198362*a(n-24) +89833*a(n-25) -71049*a(n-26) -21758*a(n-27) +18377*a(n-28) +3761*a(n-29) -3351*a(n-30) -439*a(n-31) +409*a(n-32) +31*a(n-33) -30*a(n-34) -a(n-35) +a(n-36)

%e Some solutions for n=4

%e ..0..5....5..4....3..1....3..0....1..4....3..0....2..4....1..5....2..5....3..1

%e ..0..5....4..5....0..4....0..4....2..5....0..3....3..3....3..5....2..5....2..4

%e ..3..3....4..5....0..4....5..5....2..5....1..2....4..4....5..3....2..5....5..3

%e ..1..5....4..5....2..2....5..5....2..5....3..5....3..5....3..5....5..4....3..5

%e ..3..3....4..5....1..5....5..5....2..5....3..5....3..5....5..3....4..5....3..5

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 08 2012