A208710 Number of 3 X n 0..1 arrays with new values 0..1 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
4, 32, 196, 1268, 8128, 52184, 334948, 2149988, 13800400, 88582472, 568596052, 3649722932, 23426960800, 150373741496, 965223885508, 6195610615940, 39768587869168, 255267911291816, 1638522010126516, 10517398618896212
Offset: 1
Keywords
Examples
Some solutions for n=4: 0 0 0 1 0 0 1 0 0 1 0 1 0 1 1 0 0 0 1 0 0 1 0 1 0 0 1 1 0 1 0 0 1 0 0 1 1 1 1 0 1 0 0 1 1 0 0 0 0 1 1 0 1 0 1 1 0 1 0 0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A208709.
Formula
Empirical: a(n) = 5*a(n-1) + 9*a(n-2) + a(n-3) - 2*a(n-4).
Empirical g.f.: 4*x*(1 + 3*x - x^3) / ((1 + x)*(1 - 6*x - 3*x^2 + 2*x^3)). - Colin Barker, Jul 06 2018
Comments