A129877 Sequence i_{a_n} arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition), where i_n is A129876, a_n is A129878.

2, 0, 6, 12, 58, 220, 958, 4184

Offset: 1

Author

N. J. A. Sloane, May 26 2007

Keywords

• nonn
• more

References

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

Formula

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