A210045 Number of (n+1)X2 0..2 arrays containing all values 0..2 with every 2X2 subblock having two distinct values, and new values 0..2 introduced in row major order

0, 9, 75, 475, 2695, 14443, 74831, 379459, 1896807, 9388731, 46152447, 225762931, 1100476759, 5350600939, 25966867823, 125848830499, 609324773703, 2948038268955, 14255607687903, 68907738083539, 332985156888631

Offset

1,2

Comments

Column 1 of A210052

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -6*a(n-2) -20*a(n-3) -8*a(n-4).

Empirical G.f.: x^2*(3+2*x)^2/((1-3*x-2*x^2)*(1-4*x-4*x^2)). [Colin Barker, Mar 23 2012]

Example

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

Crossrefs

Sequence in context: A339483 A274311 A281804 * A125397 A095249 A190983

Adjacent sequences: A210042 A210043 A210044 * A210046 A210047 A210048

Keyword

nonn

Author

R. H. Hardin Mar 16 2012

Status

approved