A229366 Number of n X 2 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 antidiagonally.
8, 38, 184, 869, 4144, 19675, 93589, 444824, 2114934, 10054148, 47798953, 227238276, 1080310539, 5135871337, 24416324712, 116077006646, 551838764656, 2623482504621, 12472231233800, 59293915534091, 281887688707501
Offset: 1
Keywords
Examples
Some solutions for n=4: 1 0 0 0 0 2 2 1 2 1 1 0 2 1 0 1 0 1 0 2 1 0 1 0 0 0 0 2 0 1 1 0 0 0 1 2 0 2 2 0 1 0 1 2 1 0 0 0 0 0 2 0 2 0 1 0 1 0 1 0 1 0 2 0 2 0 1 2 2 0 1 2 1 0 2 2 1 2 2 0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Column 2 of A229372.
Formula
Empirical: a(n) = 2*a(n-1) + 13*a(n-2) + 3*a(n-3) - 13*a(n-4) + 4*a(n-5).
Empirical g.f.: x*(8 + 22*x + 4*x^2 - 17*x^3 + 4*x^4) / (1 - 2*x - 13*x^2 - 3*x^3 + 13*x^4 - 4*x^5). - Colin Barker, Sep 14 2018