A281403 Number of 4Xn 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 36, 438, 1020, 2146, 3736, 6276, 10740, 18472, 31360, 53204, 90516, 153772, 260532, 440880, 745272, 1257700, 2118908, 3564884, 5989652, 10050168, 16842128, 28191540, 47137476, 78733948, 131381268, 219031808, 364842376, 607222340

Offset

1,2

Comments

Row 4 of A281400.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +6*a(n-3) -5*a(n-4) +3*a(n-6) -2*a(n-7) +2*a(n-8) -a(n-10) for n>16

Example

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

Crossrefs

Cf. A281400.

Sequence in context: A178690 A370225 A222781 * A256149 A244498 A110693

Adjacent sequences: A281400 A281401 A281402 * A281404 A281405 A281406

Keyword

nonn

Author

R. H. Hardin, Jan 21 2017

Status

approved