A209013 Number of n X 2 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it.
12, 130, 1430, 15724, 172936, 1901964, 20918008, 230058424, 2530206824, 27827480224, 306049553920, 3365965156848, 37019238613696, 407141477256160, 4477784761704800, 49247147465796160, 541625304181537792
Offset: 1
Keywords
Examples
Some solutions for n=4: 1 0 3 0 1 2 0 1 0 2 1 0 2 3 3 1 0 2 1 3 2 3 0 2 2 3 3 0 2 1 2 3 1 0 1 1 1 2 0 1 3 1 1 0 3 3 1 1 1 0 1 3 0 3 3 3 3 1 1 0 1 0 3 2 2 0 2 0 2 2 3 1 1 0 0 1 0 0 2 0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A209019.
Formula
Empirical: a(n) = 8*a(n-1) + 38*a(n-2) - 52*a(n-3) - 40*a(n-4) + 44*a(n-5) - 12*a(n-6).
Empirical g.f.: 2*x*(6 + 17*x - 33*x^2 - 16*x^3 + 22*x^4 - 2*x^5) / (1 - 8*x - 38*x^2 + 52*x^3 + 40*x^4 - 44*x^5 + 12*x^6). - Colin Barker, Jul 07 2018
Comments