A234116 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1.

145, 1361, 12593, 116801, 1082977, 10041953, 93113761, 863396401, 8005833073, 74233997105, 688333901137, 6382568345057, 59182293086657, 548767146042305, 5088437180610625, 47182476443409233, 437498981379983185

Offset: 1

Author

R. H. Hardin, Dec 19 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 2 of A234122.

Formula

Empirical: a(n) = 10*a(n-1) - 4*a(n-2) - 26*a(n-3) + 5*a(n-4).

Empirical g.f.: x*(145 - 89*x - 437*x^2 + 85*x^3) / (1 - 10*x + 4*x^2 + 26*x^3 - 5*x^4). - Colin Barker, Oct 12 2018