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

1,1

Links

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

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

Example

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

Crossrefs

Column 2 of A234122.

Sequence in context: A296972 A365204 A269015 * A232151 A264284 A008377

Adjacent sequences: A234113 A234114 A234115 * A234117 A234118 A234119

Keyword

nonn

Author

R. H. Hardin, Dec 19 2013

Status

approved