A241329 Number of 2 X n 0..3 arrays with no element equal to fewer vertical neighbors than horizontal neighbors, with new values 0..3 introduced in row major order.

2, 8, 59, 530, 4877, 45057, 416533, 3851085, 35606121, 329205872, 3043762177, 28141931363, 260193887579, 2405693427789, 22242493569775, 205649030142198, 1901384099152245, 17579764368539693, 162538497819201097

Offset

1,1

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 26*a(n-2) + 2*a(n-3) + 28*a(n-4) - 6*a(n-5) - 9*a(n-6) for n>8.

Empirical g.f.: x*(2 - 16*x + 15*x^2 + 26*x^3 - 21*x^4 - 17*x^5 + 5*x^6 + 3*x^7) / ((1 - x)*(1 - x - x^2)*(1 - 10*x + 6*x^2 + 9*x^3)). - Colin Barker, Oct 29 2018

Example

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

Crossrefs

Row 2 of A241328.

Sequence in context: A162072 A162073 A162065 * A346065 A349585 A178165

Adjacent sequences: A241326 A241327 A241328 * A241330 A241331 A241332

Keyword

nonn

Author

R. H. Hardin, Apr 19 2014

Status

approved