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
Keywords
Examples
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
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A218064.
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
Comments