A210328 1/4 of the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two or three distinct clockwise edge differences.

39, 406, 4200, 43519, 450903, 4672093, 48410727, 501617911, 5197622367, 53856299887, 558043855647, 5782293854059, 59914506914643, 620817315376591, 6432734895246807, 66654194749276315, 690652071068485899

Offset

1,1

Comments

Column 1 of A210335.

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 7*a(n-2) - 108*a(n-3) + 22*a(n-4) + 258*a(n-5) + 124*a(n-6).

Empirical g.f.: x*(39 - 62*x - 399*x^2 + 173*x^3 + 1065*x^4 + 496*x^5) / ((1 + 2*x)*(1 - 14*x + 35*x^2 + 38*x^3 - 98*x^4 - 62*x^5)). - Colin Barker, Jul 15 2018

Example

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

Crossrefs

Cf. A210335.

Sequence in context: A266172 A229601 A210335 * A231993 A357958 A229517

Adjacent sequences: A210325 A210326 A210327 * A210329 A210330 A210331

Keyword

nonn

Author

R. H. Hardin, Mar 20 2012

Status

approved