A243634 Number of length n+2 0..n arrays with no three unequal elements in a row and new values 0..n introduced in 0..n order.

4, 9, 21, 51, 127, 324, 844, 2243, 6073, 16737, 46905, 133556, 386062, 1132107, 3365627, 10137559, 30920943, 95457178, 298128278, 941574417, 3006040523, 9697677885, 31602993021, 104001763258, 345524136076, 1158570129917

Offset

1,1

Comments

Diagonal of A243641.

Links

R. H. Hardin, Table of n, a(n) for n = 1..209

Example

Some solutions for n=6
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....0....1....1....1....1....1....0....1....0....1....1....0....1....0
..1....0....1....0....1....1....1....1....1....0....0....0....1....1....0....1
..1....1....1....0....2....0....2....1....1....1....1....0....0....0....1....1
..2....1....0....0....1....1....2....1....1....0....1....1....0....0....1....1
..2....2....0....0....1....0....1....2....2....0....1....1....2....1....2....1
..2....1....2....1....3....0....1....2....2....2....1....1....2....1....2....0
..2....1....2....0....3....1....1....1....2....0....0....0....1....0....1....0

Crossrefs

Cf. A247100.

Sequence in context: A243638 A243639 A243640 * A076861 A374943 A048391

Adjacent sequences: A243631 A243632 A243633 * A243635 A243636 A243637

Keyword

nonn

Author

R. H. Hardin, Jun 08 2014

Status

approved