A275506 Number of 6 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,-1) and new values introduced in order 0..2.

24, 104, 516, 2628, 13384, 68080, 346528, 1763408, 8974288, 45670736, 232422608, 1182818704, 6019467984, 30633598480, 155897059664, 793373760912, 4037548401360, 20547436657936, 104567700792400, 532154167518352

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 10*a(n-2) + 4*a(n-3) - 4*a(n-4) for n>5.

Empirical g.f.: 4*x*(6 + 8*x - 9*x^2 - 14*x^3 + 5*x^4) / (1 - 3*x - 10*x^2 - 4*x^3 + 4*x^4). - Colin Barker, Feb 04 2019

Example

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

Crossrefs

Row 6 of A275504.

Sequence in context: A304415 A268804 A186932 * A185743 A027265 A044275

Adjacent sequences: A275503 A275504 A275505 * A275507 A275508 A275509

Keyword

nonn

Author

R. H. Hardin, Jul 30 2016

Status

approved