A198246 Number of 2nX2n 0..4 arrays with values 0..4 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors

1, 5, 1675, 14520192, 1683040515731

Offset

1,2

Comments

Diagonal of A198253

Links

Table of n, a(n) for n=1..5.

Example

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

Crossrefs

Sequence in context: A375693 A237914 A057199 * A122465 A203683 A330057

Adjacent sequences: A198243 A198244 A198245 * A198247 A198248 A198249

Keyword

nonn

Author

R. H. Hardin Oct 22 2011

Status

approved