A243599 Number of length n+2 0..n arrays with no three elements in a row with pattern aba (with a!=b) and new values 0..n introduced in 0..n order.

3, 9, 28, 96, 365, 1533, 7049, 35166, 188834, 1084179, 6618471, 42756207, 291120550, 2081922514, 15590248867, 121920095673, 993343650911, 8414029179364, 73953763887276, 673316834487161, 6340176007793059, 61657373569634585

Offset: 1

Author

R. H. Hardin, Jun 07 2014

Keywords

• nonn

Comments

Diagonal of A243607.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..121

Crossrefs

Cf. A243607.