A206688 Number of nX4 0..3 arrays with no element equal to another within two positions in the same row or column, and new values 0..3 introduced in row major order

2, 36, 176, 916, 4704, 24492, 127008, 660888, 3436488, 17884080, 93059016, 484334480, 2520695968, 13119605656, 68284077520, 355405952496, 1849822022856, 9628019156288, 50112266984832, 260826450827576, 1357560738338768

Offset

1,1

Comments

Column 4 of A206692

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -8*a(n-2) -48*a(n-3) +48*a(n-4) +140*a(n-5) +67*a(n-6) -968*a(n-7) +1564*a(n-8) -586*a(n-9) -1008*a(n-10) -32*a(n-11) +1304*a(n-12) +80*a(n-13) -512*a(n-14) for n>15

Example

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

Crossrefs

Sequence in context: A227927 A007757 A141217 * A226419 A025531 A099903

Adjacent sequences: A206685 A206686 A206687 * A206689 A206690 A206691

Keyword

nonn

Author

R. H. Hardin Feb 11 2012

Status

approved