A207174 Number of 6 X n 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 0 1 vertically.

12, 144, 396, 1989, 6513, 15789, 54208, 182081, 515760, 1608288, 5222049, 15774129, 48430957, 153161876, 472757845, 1455155232, 4543272108, 14099458893, 43567325145, 135359672373, 420297279776, 1301704097801, 4038233202624

Offset

1,1

Comments

Row 6 of A207169.

Links

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

Formula

Empirical: a(n) = a(n-1) + 21*a(n-3) + 5*a(n-4) + 5*a(n-5) - 75*a(n-6) - 50*a(n-7) + 125*a(n-9) for n>11.

Empirical g.f.: x*(12 + 132*x + 252*x^2 + 1341*x^3 + 1440*x^4 + 180*x^5 - 5150*x^6 - 9425*x^7 - 3500*x^8 + 10125*x^9 + 10000*x^10) / (1 - x - 21*x^3 - 5*x^4 - 5*x^5 + 75*x^6 + 50*x^7 - 125*x^9). - Colin Barker, Jun 21 2018

Example

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

Crossrefs

Cf. A207169.

Sequence in context: A208070 A207603 A207029 * A207457 A208120 A207370

Adjacent sequences: A207171 A207172 A207173 * A207175 A207176 A207177

Keyword

nonn

Author

R. H. Hardin, Feb 15 2012

Status

approved