A237560 Number of (n+1) X (1+1) 0..2 arrays with the upper median plus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.

81, 316, 1256, 4984, 19900, 78144, 311512, 1227648, 4896848, 19273664, 76861056, 302658560, 1207072128, 4752337152, 18952790656, 74623190528, 297608324608, 1171752619008, 4673101527552, 18399231225856, 73378645568512

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-2) + 140*a(n-4) + 632*a(n-6) + 864*a(n-8) for n>9.

Empirical g.f.: x*(81 + 316*x + 932*x^2 + 3720*x^3 + 3536*x^4 + 13968*x^5 + 4880*x^6 + 17600*x^7 + 1024*x^8) / (1 - 4*x^2 - 140*x^4 - 632*x^6 - 864*x^8). - Colin Barker, Oct 23 2018

Example

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

Crossrefs

Column 1 of A237567.

Sequence in context: A237557 A237550 A237567 * A237332 A237325 A158776

Adjacent sequences: A237557 A237558 A237559 * A237561 A237562 A237563

Keyword

nonn

Author

R. H. Hardin, Feb 09 2014

Status

approved