%I #10 Oct 26 2023 08:26:09
%S 1,14,19164,6941592576
%N Acyclic orientations of Hamming graph (K_n) x (K_n).
%C 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.
%D Martin Harborth, Structural analysis of shop scheduling problems, PhD thesis, OttovonGuerickeUniv. Magdeburg, GCAVerlag, 1999. (in German)
%H H. BrĂ¤sel, M. Harborth, T. Tautenhahn and P. Willenius, <a href="https://doi.org/10.1023/A:1018938915709">On the set of solutions of the open shop problem</a>, Ann. Oper. Res. 92 (1999) 241263.
%K nonn,nice,hard,more
%O 1,2
%A Martin Harborth (Martin.Harborth(AT)vt.siemens.de)
