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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A203913

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences:  A203906 A203907 A203908 * A203910 A203911 A203912

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 07 2012

STATUS

approved

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Last modified December 11 12:33 EST 2019. Contains 329916 sequences. (Running on oeis4.)