A203544 Number of nX2 0..4 arrays with every nonzero element less than or equal to some NW, E or S neighbor.

1, 25, 430, 4773, 48046, 504464, 5448482, 58647145, 627364147, 6706865204, 71775620385, 768373504745, 8224400451591, 88022968265234, 942088675077877, 10083142901494821, 107919728815665281, 1155059263104904968

Offset

1,2

Comments

Column 2 of A203550

Links

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

Formula

Empirical: a(n) = 25*a(n-1) -260*a(n-2) +1700*a(n-3) -7878*a(n-4) +25276*a(n-5) -56108*a(n-6) +90339*a(n-7) -109634*a(n-8) +103867*a(n-9) -84017*a(n-10) +52577*a(n-11) -21631*a(n-12) +6561*a(n-13)

Example

Some solutions for n=5
..4..3....2..0....1..4....2..0....0..4....1..0....1..0....1..4....2..0....3..2
..4..3....4..3....2..4....3..4....0..4....2..3....4..0....2..4....2..3....3..3
..4..2....4..3....0..4....3..4....0..4....1..3....4..1....2..4....0..3....3..4
..4..3....4..2....4..4....4..4....4..4....3..3....4..4....4..4....3..3....4..4
..4..4....4..4....0..4....2..4....1..4....0..3....0..2....2..4....3..3....4..4

Crossrefs

Sequence in context: A021714 A056090 A020448 * A021704 A019742 A019722

Adjacent sequences: A203541 A203542 A203543 * A203545 A203546 A203547

Keyword

nonn

Author

R. H. Hardin, Jan 02 2012

Status

approved