A250513 Number of (n+1)X(2+1) 0..3 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction

889, 14660, 205022, 2817780, 36999777, 480626844, 6146257386, 78207667892, 989461227857, 12490767516140, 157338705492038, 1979999186165612, 24895912443954313, 312904888051577996, 3931444944701135850

Offset

1,1

Comments

Column 2 of A250519

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -25*a(n-2) -1400*a(n-3) +5769*a(n-4) +23616*a(n-5) -132975*a(n-6) -127632*a(n-7) +1074132*a(n-8) +385732*a(n-9) -4202228*a(n-10) -1161728*a(n-11) +8517056*a(n-12) +2583408*a(n-13) -9166944*a(n-14) -3219264*a(n-15) +4980096*a(n-16) +2018304*a(n-17) -1078272*a(n-18) -497664*a(n-19)

Example

Some solutions for n=2
..0..3..0....1..0..2....2..0..3....1..0..3....3..0..3....2..1..1....2..0..1
..0..0..2....0..1..2....0..0..2....0..1..3....0..0..1....1..2..2....0..1..3
..3..3..2....0..1..1....2..0..2....2..2..1....1..2..2....3..2..3....2..1..3

Crossrefs

Sequence in context: A183751 A231954 A224338 * A252577 A202528 A006916

Adjacent sequences: A250510 A250511 A250512 * A250514 A250515 A250516

Keyword

nonn

Author

R. H. Hardin, Nov 24 2014

Status

approved