A281249 Number of nX4 0..2 arrays with no element equal to more than one of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

1, 139, 8489, 197429, 3291920, 47427679, 622370435, 7668286112, 90290912746, 1027352752428, 11380794989335, 123393170675013, 1314462960605872, 13797631263124064, 143031796147222229, 1466895880313669174

Offset

1,2

Comments

Column 4 of A281251.

Links

R. H. Hardin, Table of n, a(n) for n = 1..163

Example

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

Crossrefs

Cf. A281251.

Sequence in context: A223163 A158527 A201174 * A302089 A188452 A183491

Adjacent sequences: A281246 A281247 A281248 * A281250 A281251 A281252

Keyword

nonn

Author

R. H. Hardin, Jan 18 2017

Status

approved