A243517 Number of length n+2 0..8 arrays with no three elements in a row with pattern aba or abb (with a!=b) and new values 0..8 introduced in 0..8 order.

3, 5, 10, 25, 77, 280, 1157, 5296, 26406, 141585, 807064, 4837587, 30181075, 194210670, 1279159631, 8571132698, 58153599684, 398124806735, 2743173705258, 18987825983429, 131858977691833, 917797527716980, 6398758306106345

Offset: 1

Author

R. H. Hardin, Jun 05 2014

Keywords

• nonn

Examples

			Some solutions for n=5:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....0....0....0....1....1....1....0....1....1....1
..2....2....2....2....2....2....1....0....0....2....2....2....0....2....2....2
..3....3....3....3....3....3....2....0....0....0....3....3....1....0....3....3
..4....1....0....0....0....0....3....0....0....3....4....1....2....3....1....4
..5....0....1....4....2....2....0....1....0....4....1....0....3....4....2....1
..0....4....3....5....1....4....4....2....0....2....3....2....4....0....3....5
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Column 8 of A243519.

Formula

Empirical: a(n) = 23*a(n-1) - 212*a(n-2) + 1010*a(n-3) - 2669*a(n-4) + 3887*a(n-5) - 2878*a(n-6) + 840*a(n-7).

Empirical g.f.: x*(3 - 64*x + 531*x^2 - 2175*x^3 + 4579*x^4 - 4607*x^5 + 1680*x^6) / ((1 - x)^2*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 7*x)). - Colin Barker, Nov 02 2018