A183616 1/120 the number of (n+1) X 4 0..4 arrays with every 2 X 2 subblock containing four distinct values.

36, 528, 7792, 115760, 1724208, 25713200, 383674672, 5726373936, 85476349744, 1275953305136, 19047317685552, 284339706389552, 4244663837569840, 63365088706048560, 945926138351149360, 14120972327885029424

Offset

1,1

Comments

Column 3 of A183622.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 21*a(n-1) - 84*a(n-2) - 112*a(n-3) + 192*a(n-4).

Empirical g.f.: 4*x*(9 - 57*x - 68*x^2 + 128*x^3) / ((1 - 5*x - 12*x^2)*(1 - 16*x + 16*x^2)). - Colin Barker, Mar 30 2018

Example

Some solutions with the first square being 0123 for 3 X 4:
  0 1 2 1    0 1 0 4    0 1 0 1    0 1 0 1    0 1 0 3
  2 3 0 4    2 3 2 3    2 3 2 3    2 3 2 4    2 3 2 4
  1 4 1 2    0 4 1 4    1 0 1 0    4 0 1 0    0 4 0 3

Crossrefs

Cf. A183622.

Sequence in context: A090408 A268635 A233101 * A008657 A134289 A329913

Adjacent sequences: A183613 A183614 A183615 * A183617 A183618 A183619

Keyword

nonn

Author

R. H. Hardin, Jan 06 2011

Status

approved