A209709 1/4 the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having distinct clockwise edge differences.

24, 175, 1241, 8876, 63280, 451762, 3223192, 23003132, 164145204, 1171382040, 8359002576, 59650984184, 425673977552, 3037655024816, 21676983770448, 154689108964032, 1103876214994624, 7877368106279456, 56213657087788288

Offset

1,1

Comments

Column 1 of A209716.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 34*a(n-2) + 30*a(n-3) - 76*a(n-4) - 24*a(n-5) + 16*a(n-6).

Empirical g.f.: x*(24 + 127*x + 75*x^2 - 276*x^3 - 92*x^4 + 64*x^5) / (1 - 2*x - 34*x^2 - 30*x^3 + 76*x^4 + 24*x^5 - 16*x^6). - Colin Barker, Jul 12 2018

Example

Some solutions for n=4:
..0..1....0..2....3..2....0..0....0..1....2..0....3..3....1..3....3..3....3..1
..0..3....0..3....2..0....1..3....0..3....2..3....2..0....1..0....0..1....1..0
..2..2....2..2....2..3....2..1....0..1....2..0....0..3....3..1....2..3....3..1
..3..0....3..0....2..0....0..2....3..0....2..3....1..1....1..0....2..0....1..0
..3..2....0..1....1..2....3..3....1..1....0..2....3..0....0..2....1..2....3..2

Crossrefs

Cf. A209716.

Sequence in context: A166756 A268623 A209716 * A209986 A297522 A165187

Adjacent sequences: A209706 A209707 A209708 * A209710 A209711 A209712

Keyword

nonn

Author

R. H. Hardin, Mar 11 2012

Status

approved