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

1,1

Comments

Diagonal of A243607.

Links

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

Example

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

Crossrefs

Cf. A243607.

Sequence in context: A047027 A366859 A148931 * A148932 A151421 A148933

Adjacent sequences: A243596 A243597 A243598 * A243600 A243601 A243602

Keyword

nonn

Author

R. H. Hardin, Jun 07 2014

Status

approved