A218065 Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random 0..1 2 X n array.

4, 6, 18, 42, 108, 268, 676, 1694, 4258, 10690, 26852, 67436, 169372, 425382, 1068370, 2683258, 6739132, 16925644, 42509556, 106764750, 268144706, 673458066, 1691421684, 4248085292, 10669266476, 26796365718, 67300335730, 169027965834

Offset

1,1

Comments

Row 2 of A218064.

Links

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

Formula

Empirical: a(n) = a(n-1) + 4*a(n-2) + a(n-3) - 3*a(n-4) - 2*a(n-5).

Empirical g.f.: 2*x*(2 + x - 2*x^2 - 2*x^3) / ((1 - x)*(1 + x)*(1 - x - 3*x^2 - 2*x^3)). - Colin Barker, Jul 23 2018

Example

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

Crossrefs

Cf. A218064.

Sequence in context: A064403 A235344 A060667 * A005959 A057393 A196570

Adjacent sequences: A218062 A218063 A218064 * A218066 A218067 A218068

Keyword

nonn

Author

R. H. Hardin, Oct 19 2012

Status

approved