A281696 Number of 4Xn 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 222, 19326, 402470, 7497214, 126719222, 1847808312, 25489973264, 335106626139, 4243531978116, 52250869377772, 628947105706014, 7431279191300006, 86458169278267534, 992830171072101269

Offset

1,2

Comments

Row 4 of A281693.

Links

R. H. Hardin, Table of n, a(n) for n = 1..109

Example

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

Crossrefs

Cf. A281693.

Sequence in context: A043499 A251059 A220230 * A280311 A268024 A267931

Adjacent sequences: A281693 A281694 A281695 * A281697 A281698 A281699

Keyword

nonn

Author

R. H. Hardin, Jan 27 2017

Status

approved