A283692 Number of 2 X n 0..1 arrays with no 1 equal to more than two of its horizontal, diagonal and antidiagonal neighbors.

4, 16, 49, 161, 548, 1824, 6081, 20353, 68036, 227376, 760145, 2541153, 8494692, 28397120, 94929633, 317342017, 1060849668, 3546339664, 11855139953, 39630819361, 132482782884, 442879752544, 1480512941569, 4949240890113

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) + 3*a(n-3) - 6*a(n-4) - 8*a(n-5).

Empirical g.f.: x*(4 + 4*x - 3*x^2 - 14*x^3 - 8*x^4) / ((1 + x + 2*x^2)*(1 - 4*x + x^2 + 4*x^3)). - Colin Barker, Feb 21 2019

Example

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

Crossrefs

Row 2 of A283691.

Sequence in context: A114185 A188516 A188501 * A173712 A085697 A262268

Adjacent sequences: A283689 A283690 A283691 * A283693 A283694 A283695

Keyword

nonn

Author

R. H. Hardin, Mar 14 2017

Status

approved