A280311 Number of nX4 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

1, 222, 20274, 1047790, 43973846, 1638451216, 56602534187, 1855013487412, 58477471703834, 1789245480207404, 53466135036128845, 1567267054619722560, 45216089994262687510, 1287122022861142748302, 36222158292582837870301

Offset

1,2

Comments

Column 4 of A280313.

Links

R. H. Hardin, Table of n, a(n) for n = 1..89

Example

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

Crossrefs

Cf. A280313.

Sequence in context: A251059 A220230 A281696 * A268024 A267931 A268017

Adjacent sequences: A280308 A280309 A280310 * A280312 A280313 A280314

Keyword

nonn

Author

R. H. Hardin, Dec 31 2016

Status

approved