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

728, 13006, 203994, 2788842, 34183816, 384541867, 4038515481, 40101448387, 380140656392, 3466036725256, 30578353593660, 262286476969644, 2195979406910544, 18004756589877141, 144956515024805883

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