A209852 1/4 the number of (n+1)X3 0..3 arrays with every 2X2 subblock having one or four distinct clockwise edge differences

182, 2829, 43091, 661963, 10137464, 155490654, 2383064182, 36538359367, 560099384524, 8586845703984, 131635724835755, 2018037972754560, 30936878781499330, 474272812069766100, 7270720913944659218

Offset

1,1

Comments

Column 2 of A209858

Links

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

Formula

Empirical: a(n) = 11*a(n-1) +139*a(n-2) -972*a(n-3) -4071*a(n-4) +28751*a(n-5) +27819*a(n-6) -332527*a(n-7) +170449*a(n-8) +1380897*a(n-9) -1533070*a(n-10) -2378942*a(n-11) +3871609*a(n-12) +1392648*a(n-13) -4192842*a(n-14) +445370*a(n-15) +1893206*a(n-16) -633950*a(n-17) -236300*a(n-18) +99664*a(n-19) +2096*a(n-20)

Example

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

Crossrefs

Sequence in context: A234982 A234975 A186125 * A321637 A023904 A035839

Adjacent sequences: A209849 A209850 A209851 * A209853 A209854 A209855

Keyword

nonn

Author

R. H. Hardin Mar 14 2012

Status

approved