A218079 Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..1 n X 3 array.

4, 8, 26, 78, 246, 762, 2370, 7372, 22916, 71264, 221580, 688986, 2142340, 6661388, 20712972, 64404986, 200261174, 622693012, 1936204472, 6020443090, 18719993212, 58208032550, 180992322576, 562778355430, 1749905592014, 5441164449786

Offset

1,1

Comments

Column 3 of A218084.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 5*a(n-4) - a(n-5) for n>6.

Empirical g.f.: 2*x*(1 - x)*(2 + 2*x - x^2 - 4*x^3 - x^4) / (1 - 2*x - 4*x^2 + 5*x^4 + x^5). - Colin Barker, Jul 24 2018

Example

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

Crossrefs

Cf. A218084.

Sequence in context: A126733 A297695 A333894 * A012982 A012952 A272588

Adjacent sequences: A218076 A218077 A218078 * A218080 A218081 A218082

Keyword

nonn

Author

R. H. Hardin, Oct 20 2012

Status

approved