A129879 Sequence a_{a_n} arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition), where a_n is A129878.

1, 0, 3, 9, 42, 182, 821, 3754

Offset

1,3

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: A249045 A183306 A057724 * A264521 A001427 A020128

Adjacent sequences: A129876 A129877 A129878 * A129880 A129881 A129882

Keyword

nonn,more

Author

N. J. A. Sloane, May 26 2007

Status

approved