A210407 Number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock having three or four distinct values, and new values 0..3 introduced in row major order.

78, 2520, 80496, 2574592, 82334080, 2633043200, 84204544256, 2692856218368, 86117376515328, 2754028420465408, 88073659990146304, 2816590245285823232, 90074383313881529600, 2880573254472884060928, 92120556023893690612992

Offset

1,1

Comments

Column 2 of A210413.

Links

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

Formula

Empirical: a(n) = 31*a(n-1) + 40*a(n-2) - 280*a(n-3) + 96*a(n-4).

Empirical g.f.: 2*x*(39 + 51*x - 372*x^2 + 128*x^3) / (1 - 31*x - 40*x^2 + 280*x^3 - 96*x^4). - Colin Barker, Jul 15 2018

Example

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

Crossrefs

Cf. A210413.

Sequence in context: A262063 A140934 A133239 * A146479 A017794 A035734

Adjacent sequences: A210404 A210405 A210406 * A210408 A210409 A210410

Keyword

nonn

Author

R. H. Hardin, Mar 21 2012

Status

approved