A231992 Number of (n+1) X (2+1) 0..1 arrays with no element having a strict majority of its horizontal and antidiagonal neighbors equal to one.

6, 32, 156, 800, 4000, 20228, 101808, 513400, 2586980, 13039568, 65717568, 331222548, 1669362032, 8413644600, 42404958708, 213722166160, 1077165216736, 5428941217444, 27362005944240, 137905229697144, 695045979384260

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 12*a(n-2) - 5*a(n-3) - 19*a(n-4) + 2*a(n-5) + 4*a(n-6).

Empirical g.f.: 2*x*(1 + x)*(3 + 4*x - 10*x^2 - x^3 + 2*x^4) / (1 - 3*x - 12*x^2 + 5*x^3 + 19*x^4 - 2*x^5 - 4*x^6). - Colin Barker, Oct 01 2018

Example

Some solutions for n=7:
..1..0..0....0..0..1....1..0..0....0..0..0....1..0..0....0..0..0....0..0..0
..0..1..0....0..0..0....0..0..0....1..1..0....0..1..0....0..0..1....1..0..1
..1..0..1....0..0..0....1..0..0....0..0..0....1..0..0....0..0..0....0..1..0
..0..0..0....0..1..1....0..0..0....1..0..0....0..0..0....0..1..1....1..0..0
..0..1..0....1..0..0....0..0..0....0..0..0....1..0..1....1..0..0....0..1..1
..1..0..0....0..0..0....1..0..1....0..0..1....0..1..0....0..0..0....0..0..0
..1..0..0....0..0..0....0..0..1....1..0..0....1..0..0....1..0..0....0..0..0
..0..0..1....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0....0..0..0

Crossrefs

Column 2 of A231997.

Sequence in context: A242542 A046725 A232331 * A292044 A006668 A232494

Adjacent sequences: A231989 A231990 A231991 * A231993 A231994 A231995

Keyword

nonn

Author

R. H. Hardin, Nov 16 2013

Status

approved