A218059 Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..1 n X 3 array.

4, 18, 74, 308, 1282, 5338, 22228, 92562, 385450, 1605108, 6684066, 27834106, 115908116, 482670130, 2009958090, 8369963828, 34854604610, 145143215386, 604412335444, 2516922821842, 10481090672106, 43645860224116

Offset

1,1

Comments

Column 3 of A218064.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 3*a(n-2) - 2*a(n-3).

Empirical g.f.: 2*x*(2 - x - 2*x^2) / (1 - 5*x + 3*x^2 + 2*x^3). - Colin Barker, Mar 09 2018

Example

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

Crossrefs

Cf. A218064.

Sequence in context: A047034 A266753 A307323 * A069008 A026560 A180140

Adjacent sequences: A218056 A218057 A218058 * A218060 A218061 A218062

Keyword

nonn

Author

R. H. Hardin, Oct 19 2012

Status

approved