A231257 Number of (n+1) X (2+1) 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..2 introduced in row major order.
3, 15, 89, 547, 3381, 20911, 129329, 799835, 4946509, 30591143, 189187465, 1170008467, 7235785189, 44748896799, 276744502881, 1711495152971, 10584548667901, 65458946997783, 404823472069561, 2503585087356803
Offset: 1
Keywords
Examples
Some solutions for n=3: ..0..0..0....0..0..1....0..0..1....0..0..0....0..0..1....0..0..1....0..0..0 ..0..0..1....0..1..2....0..1..2....0..0..0....0..1..2....0..1..0....1..1..1 ..0..1..1....1..2..0....1..2..2....0..0..0....1..2..1....1..0..0....0..0..2 ..1..1..1....2..0..0....2..2..2....0..0..0....2..1..1....0..0..0....0..2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 10*a(n-1) -29*a(n-2) +36*a(n-3) -16*a(n-4).
Empirical g.f.: x*(1 - 2*x)*(3 - 9*x + 8*x^2) / ((1 - x)*(1 - 9*x + 20*x^2 - 16*x^3)). - Colin Barker, Feb 16 2018
Comments