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A053870 Acyclic orientations of Hamming graph (K_n) x (K_n). 3
1, 14, 19164, 6941592576 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This number is equivalent to the number of plans (i.e. structural solutions) of the open shop problem with n jobs and n machines - see problems in scheduling theory.

REFERENCES

H. Braesel, M. Harborth, T. Tautenhahn and P. Willenius, On the set of solutions of the open shop problem, Ann. Oper. Res. 92 (1999) 241-263

M. Harborth, Structural analysis of shop scheduling problems, PhD thesis, Otto-von-Guericke-Univ. Magdeburg, GCA-Verlag, 1999 (in German)

LINKS

Table of n, a(n) for n=1..4.

CROSSREFS

Sequence in context: A246623 A208194 A104376 * A283840 A079176 A013754

Adjacent sequences:  A053867 A053868 A053869 * A053871 A053872 A053873

KEYWORD

nonn,nice,hard

AUTHOR

Martin Harborth (Martin.Harborth(AT)vt.siemens.de)

STATUS

approved

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Last modified April 20 09:59 EDT 2019. Contains 322309 sequences. (Running on oeis4.)