A207045 Number of (n+1) X 4 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly one clockwise edge increases.

441, 552, 750, 1272, 2094, 3408, 5850, 9792, 15966, 26880, 45024, 73656, 123486, 206976, 339648, 567600, 951390, 1565568, 2610048, 4373160, 7213662, 12005760, 20102688, 33227808, 55236702, 92416512, 153013920, 254174616, 424902750

Offset

1,1

Comments

Column 3 of A207050.

Links

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

Formula

Empirical: a(n) = 4*a(n-3) +a(n-4) for n>11.

Empirical g.f.: 3*x*(147 + 184*x + 250*x^2 - 164*x^3 - 185*x^4 - 48*x^5 + 4*x^6 + 48*x^7 + 80*x^8 + 24*x^9 + 2*x^10) / (1 - 4*x^3 - x^4). - Colin Barker, Jun 18 2018

Example

Some solutions for n=4:
..0..0..1..1....1..0..2..2....2..1..0..0....2..0..0..2....2..2..0..0
..0..0..0..1....1..1..2..2....2..0..0..0....2..0..0..0....2..0..0..0
..1..0..0..0....1..1..1..2....0..0..0..2....2..2..0..0....0..0..0..2
..1..1..0..0....0..1..1..1....0..0..1..1....2..2..2..0....0..0..1..1
..1..1..1..2....0..0..1..1....1..1..1..1....1..2..2..2....1..1..1..1

Crossrefs

Cf. A207050.

Sequence in context: A124170 A252193 A207650 * A252201 A252194 A057949

Adjacent sequences: A207042 A207043 A207044 * A207046 A207047 A207048

Keyword

nonn

Author

R. H. Hardin, Feb 14 2012

Status

approved