A229575 Number of defective 4-colorings of an n X 5 0..3 array connected horizontally, vertically, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..3 order.

20, 216, 362, 568, 924, 1576, 2852, 5440, 10780, 21880, 45012, 93232, 193676, 402664, 836932, 1738144, 3606012, 7472728, 15468212, 31983376, 66062188, 136316872, 281020452, 578816128, 1191184604, 2449475896, 5033167252, 10334767600

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 13*a(n-2) + 12*a(n-3) - 4*a(n-4) for n>7.

Empirical g.f.: 2*x*(10 + 48*x - 337*x^2 + 482*x^3 - 145*x^4 - 32*x^5 + 20*x^6) / ((1 - x)^2*(1 - 2*x)^2). - Colin Barker, Sep 19 2018

Example

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

Crossrefs

Column 5 of A229578.

Sequence in context: A121204 A128823 A141790 * A125408 A213351 A140236

Adjacent sequences: A229572 A229573 A229574 * A229576 A229577 A229578

Keyword

nonn

Author

R. H. Hardin, Sep 26 2013

Status

approved