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 2X2 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

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