A235885 Number of (n+1) X (n+1) 0..3 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2 X 2 subblock.

40, 232, 1096, 4744, 19720, 80392, 324616, 1304584, 5230600, 20946952, 83836936, 335446024

Offset

1,1

Comments

Diagonal of A235893.

Links

Table of n, a(n) for n=1..12.

Formula

Empirical: a(n) = 7*a(n-1) -14*a(n-2) +8*a(n-3).

Example

Some solutions for n=4
..3..2..3..3..3....2..1..3..0..1....0..0..1..0..1....3..1..1..0..1
..2..3..2..2..2....2..1..3..0..1....0..0..1..0..1....3..1..1..0..1
..3..2..3..3..3....2..1..3..0..1....1..1..0..1..0....3..1..1..0..1
..2..3..2..2..2....2..1..3..0..1....1..1..0..1..0....3..1..1..0..1
..3..2..3..3..3....2..1..3..0..1....1..1..0..1..0....3..1..1..0..1

Crossrefs

Cf. A235893.

Sequence in context: A235010 A235290 A074360 * A068790 A073962 A267391

Adjacent sequences: A235882 A235883 A235884 * A235886 A235887 A235888

Keyword

nonn

Author

R. H. Hardin, Jan 16 2014

Status

approved