A210780 Number of n X n 1..4 arrays with no element with value z exactly a city block distance of z from another element with value z

4, 176, 21379, 1115472, 98861559, 51104966068

Offset

1,1

Comments

Diagonal of A210788

Links

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

Example

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

Crossrefs

Sequence in context: A251695 A343610 A113254 * A127606 A041945 A300387

Adjacent sequences: A210777 A210778 A210779 * A210781 A210782 A210783

Keyword

nonn

Author

R. H. Hardin Mar 26 2012

Status

approved