A203649 1/25 the number of (n+1) X (n+1) 0..4 arrays with every 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.

9, 1517, 1116249, 3906948333, 67213191427593, 5796397762880763341

Offset

1,1

Links

Table of n, a(n) for n=1..6.

Example

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

Crossrefs

Diagonal of A203656.

Sequence in context: A231191 A217267 A300594 * A187131 A167774 A381197

Adjacent sequences: A203646 A203647 A203648 * A203650 A203651 A203652

Keyword

nonn,more

Author

R. H. Hardin, Jan 04 2012

Status

approved