A129875 Sequence t_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition).

0, 2, 4, 9, 22, 45, 120, 239

Offset

1,2

References

Jocelyn Quaintance, Combinatoric Enumeration of Two-Dimensional Proper Arrays, Discrete Math., 307 (2007), 1844-1864.

Links

Table of n, a(n) for n=1..8.

Formula

See Quaintance reference for generating functions that produce A129872-A129886.

Crossrefs

Sequence in context: A156801 A363771 A057580 * A055094 A369472 A055729

Adjacent sequences: A129872 A129873 A129874 * A129876 A129877 A129878

Keyword

nonn,more

Author

N. J. A. Sloane, May 26 2007

Status

approved