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%I #6 Mar 31 2012 12:36:58
%S 728,13006,203994,2788842,34183816,384541867,4038515481,40101448387,
%T 380140656392,3466036725256,30578353593660,262286476969644,
%U 2195979406910544,18004756589877141,144956515024805883
%N Number of (n+1)X2 0..6 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 A203913
%H R. H. Hardin, <a href="/A203909/b203909.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 54*a(n-1) -1340*a(n-2) +20282*a(n-3) -209613*a(n-4) +1569268*a(n-5) -8811864*a(n-6) +37918836*a(n-7) -126686043*a(n-8) +330947422*a(n-9) -677517012*a(n-10) +1084545362*a(n-11) -1348021991*a(n-12) +1284251736*a(n-13) -918050584*a(n-14) +475708320*a(n-15) -168477552*a(n-16) +36443520*a(n-17) -3628800*a(n-18)
%e Some solutions for n=4
%e ..4..0....4..6....0..4....1..4....1..6....5..1....4..5....6..4....2..5....2..4
%e ..1..5....6..4....2..4....6..6....1..6....1..5....3..6....4..6....1..6....1..5
%e ..5..3....4..6....1..5....6..6....3..4....1..5....5..4....4..6....1..6....5..3
%e ..3..5....4..6....4..2....6..6....4..3....0..6....3..6....6..4....2..5....2..6
%e ..5..3....4..6....5..1....6..6....1..6....3..4....5..4....4..6....1..6....5..6
%K nonn
%O 1,1
%A _R. H. Hardin_ Jan 07 2012
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