A237377 Number of (n+1) X (1+1) 0..2 arrays with the maximum plus the minimum minus the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.

81, 344, 1472, 6368, 27280, 115584, 494592, 2139648, 9166080, 38836224, 166182912, 718921728, 3079802880, 13048971264, 55837458432, 241557700608, 1034813767680, 4384454344704, 18761386033152, 81163387404288, 347697425940480

Offset

1,1

Links

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

Formula

Empirical: a(n) = 336*a(n-4) for n>5.

Empirical g.f.: x*(81 + 344*x + 1472*x^2 + 6368*x^3 + 64*x^4) / (1 - 336*x^4). - Colin Barker, Oct 22 2018

Example

Some solutions for n=5:
..1..2....1..2....1..2....2..0....1..1....1..0....0..2....2..2....2..2....2..0
..1..2....2..0....1..2....1..1....0..0....0..1....1..0....0..0....2..1....1..0
..1..1....2..2....2..0....0..1....1..2....1..1....0..1....1..0....1..2....2..1
..2..2....0..1....1..1....0..1....0..1....0..2....0..2....1..2....2..0....0..0
..2..1....1..2....0..1....0..2....2..0....1..0....2..0....1..1....1..1....0..0
..2..1....0..0....1..2....2..0....1..1....1..0....1..0....2..0....0..1....0..1

Crossrefs

Column 1 of A237384.

Sequence in context: A237384 A237249 A236096 * A237242 A236089 A236737

Adjacent sequences: A237374 A237375 A237376 * A237378 A237379 A237380

Keyword

nonn

Author

R. H. Hardin, Feb 07 2014

Status

approved