A215953 Number of horizontal, vertical and diagonal neighbor colorings of the even squares of an n X 2 array with new integer colors introduced in row major order.

1, 1, 2, 4, 12, 34, 136, 500, 2440, 10900, 61912, 322768, 2075312, 12297768, 87852160, 580849872, 4548247264, 33093252880, 281121815712, 2227152575552, 20358402201792, 174131286983712, 1701534399324544, 15604440074084672

Offset

1,3

Comments

Column 2 of A215959.

Links

R. H. Hardin, Table of n, a(n) for n = 1..122

Example

Some solutions for n=5
..0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x
..x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1
..1..x....1..x....2..x....2..x....2..x....1..x....2..x....1..x....2..x....1..x
..x..0....x..2....x..3....x..3....x..0....x..0....x..0....x..2....x..3....x..2
..0..x....0..x....1..x....0..x....1..x....2..x....0..x....3..x....4..x....2..x

Crossrefs

Sequence in context: A240904 A245310 A363202 * A209027 A069727 A148204

Adjacent sequences: A215950 A215951 A215952 * A215954 A215955 A215956

Keyword

nonn

Author

R. H. Hardin, Aug 28 2012

Status

approved