A222090 Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out left turns.

3, 31, 308, 3034, 29860, 293848, 2891636, 28455036, 280009384, 2755404412, 27114269752, 266815111088, 2625565876172, 25836603103756, 254242357913972, 2501845009992824, 24619140986161492, 242262050800828048

Offset

1,1

Comments

Column 2 of A222093.

Links

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

Formula

Empirical: a(n) = 17*a(n-1) - 90*a(n-2) + 217*a(n-3) - 258*a(n-4) + 156*a(n-5) - 44*a(n-6) + 4*a(n-7).

Empirical g.f.: x*(3 - 20*x + 51*x^2 - 63*x^3 + 49*x^4 - 18*x^5 + 2*x^6) / (1 - 17*x + 90*x^2 - 217*x^3 + 258*x^4 - 156*x^5 + 44*x^6 - 4*x^7). - Colin Barker, Aug 14 2018

Example

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

Crossrefs

Cf. A222093.

Sequence in context: A220997 A222094 A069589 * A037778 A037666 A065837

Adjacent sequences: A222087 A222088 A222089 * A222091 A222092 A222093

Keyword

nonn

Author

R. H. Hardin, Feb 07 2013

Status

approved