A228504 Number of n X 6 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally.

8, 21, 239, 1252, 9528, 59839, 413786, 2724191, 18387032, 122539084, 821945828, 5495164996, 36800032261, 246231184011, 1648269251345, 11031030456148, 73833534042745, 494158034052549, 3307432804186754, 22136531409536410

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 30*a(n-2) - 17*a(n-3) - 138*a(n-4) + 85*a(n-5) + 116*a(n-6) - 42*a(n-7) - 32*a(n-8).

Empirical g.f.: x*(8 - 3*x - 64*x^2 + 41*x^3 + 63*x^4 - 24*x^5 - 18*x^6) / (1 - 3*x - 30*x^2 + 17*x^3 + 138*x^4 - 85*x^5 - 116*x^6 + 42*x^7 + 32*x^8). - Colin Barker, Sep 12 2018

Example

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

Crossrefs

Column 6 of A228506.

Sequence in context: A240648 A231525 A228756 * A270552 A156239 A141369

Adjacent sequences: A228501 A228502 A228503 * A228505 A228506 A228507

Keyword

nonn

Author

R. H. Hardin, Aug 23 2013

Status

approved