A208067 Number of n X 6 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 1 vertically.

26, 676, 2080, 6400, 12960, 26244, 44064, 73984, 111520, 168100, 236160, 331776, 443520, 592900, 763840, 984064, 1232064, 1542564, 1887840, 2310400, 2775520, 3334276, 3944160, 4665600, 5447520, 6360484, 7344064, 8479744, 9696960

Offset

1,1

Comments

Column 6 of A208069.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 2*a(n-2) - 6*a(n-3) + 6*a(n-5) - 2*a(n-6) - 2*a(n-7) + a(n-8) for n>9.

Empirical g.f.: 2*x*(13 + 312*x + 338*x^2 + 522*x^3 + 28*x^4 - 76*x^5 + 26*x^6 + 26*x^7 - 13*x^8) / ((1 - x)^5*(1 + x)^3). - Colin Barker, Jun 27 2018

Example

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

Crossrefs

Cf. A208069.

Sequence in context: A207843 A206985 A208377 * A207932 A207849 A208838

Adjacent sequences: A208064 A208065 A208066 * A208068 A208069 A208070

Keyword

nonn

Author

R. H. Hardin, Feb 23 2012

Status

approved