A235443 Number of (n+1) X (2+1) 0..1 arrays with the difference between each 2 X 2 subblock maximum and minimum lexicographically nondecreasing rowwise and columnwise.

58, 382, 2476, 15936, 102376, 657290, 4219322, 27083638, 173846264, 1115891712, 7162725052, 45976338618, 295114433334, 1894290182854, 12159131749324, 78047432228320, 500973408338488, 3215664483364362, 20640812260995146

Offset: 1

Author

R. H. Hardin, Jan 10 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A235449.

Formula

Empirical: a(n) = 8*a(n-1) - 8*a(n-2) - 16*a(n-3) + 12*a(n-4) + 14*a(n-5) - a(n-6) - 2*a(n-7).

Empirical g.f.: 2*x*(29 - 41*x - 58*x^2 + 56*x^3 + 56*x^4 - 5*x^5 - 8*x^6) / ((1 - x - x^2)^2*(1 - 6*x - 3*x^2 + 2*x^3)). - Colin Barker, Oct 19 2018