A235876 Number of (n+1)X(n+1) 0..2 arrays with the minimum plus the upper median equal to the lower median plus the maximum in every 2X2 subblock

21, 105, 453, 1833, 7221, 28185, 109893, 429513, 1684821, 6633465, 26204133, 103802793, 412120821, 1639113945

Offset

1,1

Comments

Diagonal of A235884

Links

Table of n, a(n) for n=1..14.

Formula

Empirical: a(n) = 10*a(n-1) -35*a(n-2) +50*a(n-3) -24*a(n-4)

Example

Some solutions for n=5
..2..1..1..2..2..2....0..0..0..0..0..1....2..2..2..2..0..2....1..0..0..0..1..1
..1..2..2..1..1..1....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....0..0..0..0..2..0....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..1..2..2..1..1..1....0..0..0..0..0..1....2..2..2..2..0..2....0..1..1..1..0..0
..2..1..1..2..2..2....0..0..0..0..0..1....0..0..0..0..2..0....0..1..1..1..0..0

Crossrefs

Sequence in context: A126229 A060537 A116689 * A279763 A068986 A219631

Adjacent sequences: A235873 A235874 A235875 * A235877 A235878 A235879

Keyword

nonn

Author

R. H. Hardin, Jan 16 2014

Status

approved