A283951 Number of 2Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.

0, 0, 2, 16, 84, 408, 1926, 8776, 38912, 169456, 727914, 3091712, 13010668, 54334792, 225449486, 930278584, 3820249240, 15622389664, 63649588850, 258473068912, 1046543827972, 4226200851704, 17025631341974, 68440231400232

Offset

1,3

Comments

Row 2 of A283950.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -7*a(n-2) +8*a(n-3) -31*a(n-4) -50*a(n-5) -61*a(n-6) -84*a(n-7) -36*a(n-8).

Empirical g.f.: G.f.: 2*x^3*(1+x)^2/(-1+3*x+x^2+7*x^3+6*x^4)^2 . - R. J. Mathar, Mar 21 2017

Example

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

Crossrefs

Cf. A283950.

Sequence in context: A207880 A207263 A207757 * A207340 A207768 A207891

Adjacent sequences: A283948 A283949 A283950 * A283952 A283953 A283954

Keyword

nonn

Author

R. H. Hardin, Mar 18 2017

Status

approved