A198521 Number of n X n 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors

1, 15, 16714, 1084539825, 1814002928583853, 72341858272434900016248

Offset

1,2

Comments

Diagonal of A198528

Links

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

Example

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

Crossrefs

Sequence in context: A282945 A112614 A238634 * A354062 A212924 A068732

Adjacent sequences: A198518 A198519 A198520 * A198522 A198523 A198524

Keyword

nonn

Author

R. H. Hardin Oct 26 2011

Status

approved