A208551 Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 0 1 1 vertically.

10, 100, 330, 1089, 2508, 5776, 11020, 21025, 35670, 60516, 94710, 148225, 218680, 322624, 454968, 641601, 873090, 1188100, 1570690, 2076481, 2680260, 3459600, 4376580, 5536609, 6884878, 8561476, 10489710, 12852225, 15544560, 18800896

Offset

1,1

Comments

Column 4 of A208555.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 10*a(n-3) - 5*a(n-4) + 20*a(n-5) - 20*a(n-7) + 5*a(n-8) + 10*a(n-9) - 4*a(n-10) - 2*a(n-11) + a(n-12).

Empirical g.f.: x*(10 + 80*x + 90*x^2 + 129*x^3 + 60*x^4 + 4*x^5 - 24*x^6 + 6*x^7 + 10*x^8 - 4*x^9 - 2*x^10 + x^11) / ((1 - x)^7*(1 + x)^5). Colin Barker, Jul 03 2018

Example

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

Crossrefs

Cf. A208555.

Sequence in context: A262761 A134556 A207449 * A207308 A207114 A207394

Adjacent sequences: A208548 A208549 A208550 * A208552 A208553 A208554

Keyword

nonn

Author

R. H. Hardin, Feb 28 2012

Status

approved