OFFSET
0,13
COMMENTS
Torus solutions, i.e. solutions having an empty conflict constellation, are counted in column 1; this is caused by an interpretation of a queen not engaged in any conflict as an island in the conflict graph. Using the definition strictly, these queens should be removed from the graph and the numbers should appear in column 0, not column 1.
LINKS
M. Engelhardt, Rows n=0..16 of triangle, flattened
Matthias Engelhardt, Conflicts in the n-queens problem
Matthias Engelhardt, Conflict tables for the n-queens problem
M. R. Engelhardt, A group-based search for solutions of the n-queens problem, Discr. Math., 307 (2007), 2535-2551.
FORMULA
EXAMPLE
Triangle begins:
0;
0, 1;
0, 0, 0;
0, 0, 0, 0;
0, 0, 2, 0, 0;
0, 10, 0, 0, 0, 0;
0, 0, 0, 0, 4, 0, 0;
0, 28, 8, 4, 0, 0, 0, 0;
... - Andrew Howroyd, Dec 31 2017
for n=4, there are only the two solutions 2-4-1-3 and 3-1-4-2. Both have two conflicts So the terms for n=4 are 0 (0 solutions for n=4 having 0 conflicts), 0, 2 (the two cited above), 0 and 0. These are members 10 to 15 of the sequence.
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Matthias Engelhardt, Oct 30 2010
EXTENSIONS
Offset corrected by Andrew Howroyd, Dec 31 2017
STATUS
approved