A231051 Number of 3Xn 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero

0, 2, 50, 128, 644, 5100, 33696, 211032, 1354848, 8755256, 56382600, 362808600, 2335743720, 15038803080, 96821412760, 623339871560, 4013124023592, 25836921761608, 166340644854200, 1070917308473608, 6894671429298216

Offset

1,2

Comments

Row 3 of A231049

Links

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

Formula

Empirical: a(n) = 6*a(n-1) +18*a(n-3) +17*a(n-4) -98*a(n-5) -32*a(n-6) +6*a(n-7) -16*a(n-8) +36*a(n-9) -8*a(n-10) for n>11

Example

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

Crossrefs

Sequence in context: A027619 A076267 A050800 * A317819 A231082 A318426

Adjacent sequences: A231048 A231049 A231050 * A231052 A231053 A231054

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved