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A203909
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
1
728, 13006, 203994, 2788842, 34183816, 384541867, 4038515481, 40101448387, 380140656392, 3466036725256, 30578353593660, 262286476969644, 2195979406910544, 18004756589877141, 144956515024805883
OFFSET
1,1
COMMENTS
Column 1 of A203913
LINKS
FORMULA
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)
EXAMPLE
Some solutions for n=4
..4..0....4..6....0..4....1..4....1..6....5..1....4..5....6..4....2..5....2..4
..1..5....6..4....2..4....6..6....1..6....1..5....3..6....4..6....1..6....1..5
..5..3....4..6....1..5....6..6....3..4....1..5....5..4....4..6....1..6....5..3
..3..5....4..6....4..2....6..6....4..3....0..6....3..6....6..4....2..5....2..6
..5..3....4..6....5..1....6..6....1..6....3..4....5..4....4..6....1..6....5..6
CROSSREFS
Sequence in context: A203672 A203665 A203913 * A085479 A203664 A265103
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 07 2012
STATUS
approved