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A129876 Sequence i_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition). 4
2, 4, 14, 52, 210, 888, 3886, 17448 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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: A003500 A316363 A295760 * A038055 A006385 A322859

Adjacent sequences:  A129873 A129874 A129875 * A129877 A129878 A129879

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, May 26 2007

STATUS

approved

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Last modified August 13 19:30 EDT 2020. Contains 336451 sequences. (Running on oeis4.)