A218645 Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random 0..3 n X 2 array.

4, 16, 66, 292, 1280, 5644, 24782, 108940, 478862, 2104866, 9252000, 40667620, 178756504, 785732636, 3453724976, 15181011874, 66728857148, 293309853452, 1289257359676, 5666991817956, 24909531073894, 109491024206644

Offset

1,1

Comments

Column 2 of A218651.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 7*a(n-2) + 12*a(n-3) + 14*a(n-4) + 7*a(n-5) - 2*a(n-6) - 3*a(n-7) - a(n-8).

Empirical g.f.: 2*x*(2 + 4*x + 3*x^2 - 7*x^4 - 2*x^5 + x^6 + x^7) / (1 - 2*x - 7*x^2 - 12*x^3 - 14*x^4 - 7*x^5 + 2*x^6 + 3*x^7 + x^8). - Colin Barker, Jul 24 2018

Example

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

Crossrefs

Cf. A218651.

Sequence in context: A026883 A349730 A151242 * A273582 A183275 A024551

Adjacent sequences: A218642 A218643 A218644 * A218646 A218647 A218648

Keyword

nonn

Author

R. H. Hardin, Nov 03 2012

Status

approved