A230927 Number of black-square subarrays of (n+2)X(n+2) 0..3 arrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, no adjacent elements equal, and upper left element zero

2, 6, 102, 1242, 98296, 4092246, 1088383766, 159130979900, 148986525600652, 76371552378548280, 250772217069255837720

Offset

1,1

Comments

Diagonal of A230935

Links

Table of n, a(n) for n=1..11.

Example

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

Crossrefs

Sequence in context: A100704 A357084 A123257 * A054247 A278888 A099790

Adjacent sequences: A230924 A230925 A230926 * A230928 A230929 A230930

Keyword

nonn

Author

R. H. Hardin, Nov 01 2013

Status

approved