A233638 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 2.

90, 534, 3004, 17424, 99380, 572192, 3277236, 18825580, 107963840, 619734876, 3555590252, 20405232856, 117085241588, 671895102796, 3855486448064, 22124270945452, 126955643098236, 728515542322936, 4180454758322084

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 9*a(n-2) - 67*a(n-3) + 26*a(n-4) + 81*a(n-5) - 48*a(n-6) + 2*a(n-7).

Empirical g.f.: 2*x*(45 - 3*x - 505*x^2 + 312*x^3 + 619*x^4 - 405*x^5 + 17*x^6) / (1 - 6*x - 9*x^2 + 67*x^3 - 26*x^4 - 81*x^5 + 48*x^6 - 2*x^7). - Colin Barker, Oct 11 2018

Example

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

Crossrefs

Column 2 of A233644.

Sequence in context: A203741 A203734 A066116 * A289792 A156738 A211446

Adjacent sequences: A233635 A233636 A233637 * A233639 A233640 A233641

Keyword

nonn

Author

R. H. Hardin, Dec 14 2013

Status

approved