A281247 Number of nX2 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.

0, 0, 12, 139, 1222, 9151, 63138, 412070, 2585022, 15739317, 93614462, 546390377, 3139809956, 17808523566, 99888570784, 554920263375, 3057078206870, 16717853840323, 90826885281558, 490581957118358, 2635899256765106

Offset

1,3

Comments

Column 2 of A281251.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 13*a(n-1) -48*a(n-2) +7*a(n-3) +149*a(n-4) +96*a(n-5) -59*a(n-6) -97*a(n-7) -48*a(n-8) -11*a(n-9) -a(n-10) for n>12

Example

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

Crossrefs

Cf. A281251.

Sequence in context: A113366 A360203 A003379 * A124206 A061636 A266177

Adjacent sequences: A281244 A281245 A281246 * A281248 A281249 A281250

Keyword

nonn

Author

R. H. Hardin, Jan 18 2017

Status

approved