A233684 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 10, and no two adjacent values equal.

32, 108, 356, 1188, 3940, 13108, 43540, 144740, 480964, 1598548, 5312436, 17655684, 58676452, 195006452, 648083796, 2153846948, 7158099972, 23789267092, 79061340148, 262752815812, 873233798180, 2902108995124, 9644881349524

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 5*a(n-2) - 2*a(n-3).

Empirical g.f.: 4*x*(8 + 11*x - 5*x^2) / (1 - 2*x - 5*x^2 + 2*x^3). - Colin Barker, Oct 11 2018

Example

Some solutions for n=5:
..0..2....2..0....3..1....3..1....2..3....1..0....2..3....1..2....2..1....3..2
..2..1....3..2....2..0....2..3....3..1....3..1....0..2....2..0....0..2....2..0
..0..2....2..0....1..2....0..1....2..0....2..0....2..3....3..1....1..3....0..1
..2..3....3..2....3..1....2..3....1..2....3..2....0..1....1..0....3..2....2..0
..0..2....2..0....2..3....3..1....2..0....1..3....2..3....0..2....2..0....0..1
..1..0....1..2....3..1....2..3....0..1....3..2....0..1....1..3....1..2....2..0

Crossrefs

Column 1 of A233691.

Sequence in context: A173951 A233691 A337786 * A218068 A333582 A039464

Adjacent sequences: A233681 A233682 A233683 * A233685 A233686 A233687

Keyword

nonn

Author

R. H. Hardin, Dec 14 2013

Status

approved