A253360 Number of (n+2) X (1+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally and vertically.

152, 272, 560, 976, 1904, 3472, 6544, 12048, 22704, 41680, 78800, 144464, 273264, 501008, 947472, 1737360, 3285296, 6024272, 11391824, 20889040, 39501296, 72432784, 136970896, 251161104, 474946992, 870902224, 1646880464, 3019856720

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-2) - 3*a(n-4) + 4*a(n-6).

Empirical g.f.: 8*x*(19 + 34*x - 6*x^2 - 14*x^3 + 15*x^4 + 48*x^5) / (1 - 4*x^2 + 3*x^4 - 4*x^6). - Colin Barker, Dec 11 2018

Example

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

Crossrefs

Column 1 of A253367.

Sequence in context: A185394 A097640 A253367 * A252363 A248816 A038857

Adjacent sequences: A253357 A253358 A253359 * A253361 A253362 A253363

Keyword

nonn

Author

R. H. Hardin, Dec 30 2014

Status

approved