A253519 Number of (n+1)X(3+1) 0..2 arrays with every 2X2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically

2180, 10706, 30013, 84684, 256914, 791232, 2419612, 7338525, 22126888, 66487395, 199430934, 597738095, 1791132691, 5367324020, 16086064541, 48218959866, 144563723032, 433475686645, 1299938039440, 3898720339161, 11693742463489

Offset

1,1

Comments

Column 3 of A253524

Links

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

Formula

Empirical: a(n) = 12*a(n-1) -61*a(n-2) +172*a(n-3) -295*a(n-4) +316*a(n-5) -207*a(n-6) +76*a(n-7) -12*a(n-8) for n>16

Example

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

Crossrefs

Sequence in context: A137874 A137875 A020425 * A281562 A254417 A254424

Adjacent sequences: A253516 A253517 A253518 * A253520 A253521 A253522

Keyword

nonn

Author

R. H. Hardin, Jan 03 2015

Status

approved