A229475 Number of defective 4-colorings of an n X 4 0..3 array connected horizontally, antidiagonally and vertically with exactly one mistake, and colors introduced in row-major 0..3 order.

6, 248, 3328, 36116, 360912, 3443856, 31875248, 288634368, 2570642816, 22599003712, 196602867456, 1695703281408, 14520402611968, 123579905038336, 1046236716429312, 8817070242804736, 74007384618897408, 618990518429175808

Offset

1,1

Links

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

Formula

Empirical: a(n) = 24*a(n-1) - 224*a(n-2) + 1096*a(n-3) - 3360*a(n-4) + 6976*a(n-5) - 9744*a(n-6) + 8704*a(n-7) - 4096*a(n-8) for n > 9.

Empirical g.f.: 2*x*(3 + 52*x - 640*x^2 + 2610*x^3 - 6024*x^4 + 7944*x^5 - 2824*x^6 - 4736*x^7 + 10240*x^8) / (1 - 12*x + 40*x^2 - 68*x^3 + 64*x^4)^2. - Colin Barker, Sep 18 2018

Example

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

Crossrefs

Column 4 of A229479.

Sequence in context: A322559 A229631 A206307 * A281054 A056238 A335158

Adjacent sequences: A229472 A229473 A229474 * A229476 A229477 A229478

Keyword

nonn

Author

R. H. Hardin, Sep 24 2013

Status

approved