A200573 Number of n X 2 0..2 arrays with no average of any element and its horizontal and vertical neighbors equal to one.

6, 36, 174, 922, 5202, 29180, 163706, 919924, 5171420, 29068726, 163403454, 918546962, 5163485576, 29025793202, 163164480016, 917206531060, 5155949803838, 28983459159770, 162926511803678, 915868877073788

Offset

1,1

Links

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

Robert Israel, Maple-assisted proof of empirical formula

Formula

Empirical: a(n) = 5*a(n-1) +8*a(n-2) -20*a(n-3) -23*a(n-4) -52*a(n-5) +25*a(n-6) +254*a(n-7) +62*a(n-8) -134*a(n-9) -88*a(n-10) -360*a(n-11) +176*a(n-12) -168*a(n-13) +184*a(n-14).

Empirical formula confirmed by Robert Israel, Jun 28 2018 (see link).

Example

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

Crossrefs

Column 2 of A200579.

Sequence in context: A213294 A293886 A132165 * A224130 A283197 A218265

Adjacent sequences: A200570 A200571 A200572 * A200574 A200575 A200576

Keyword

nonn

Author

R. H. Hardin, Nov 19 2011

Status

approved