A181499 - OEIS

%I #17 Jan 19 2019 03:46:10

%S 0,1,0,0,0,0,0,0,0,0,0,0,2,0,0,10,0,0,0,0,0,0,0,0,4,0,0,0,28,0,0,8,4,

%T 0,0,0,0,0,64,0,28,0,0,0,0,0,0,232,0,96,24,0,0,0,0,0,0,240,0,372,112,

%U 0,0,0,0,0,88,0,0,328,1252,872,140,0,0,0,0,0,0,0,0,3016,5140,4696,1316,32,0,0,0,0,0

%N Triangle read by rows: number of solutions of n queens problem for given n and given number of conflicts

%H Matthias Engelhardt, <a href="/A181499/b181499.txt">Table of n, a(n) for n = 0..152</a> (corrected by Michel Marcus, Jan 19 2019)

%H M. Engelhardt, <a href="http://nqueens.de/sub/Conflicts.en.html">Conflicts in the n-queens problem</a>

%H M. Engelhardt, <a href="http://nqueens.de/sub/ConflictTables.en.html">Conflict tables for the n-queens problem</a>

%H M. R. Engelhardt, <a href="http://dx.doi.org/10.1016/j.disc.2007.01.007">A group-based search for solutions of the n-queens problem</a>, Discr. Math., 307 (2007), 2535-2551.

%F Row sum = A000170 (number of n queens placements)

%F Column 0 has same values as A007705 (torus n queens solutions)

%F Column 1 is always zero.

%e 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.

%Y Cf. A000170, A007705, A181500, A181501, A181502.

%K nonn,tabl

%O 0,13

%A _Matthias Engelhardt_, Oct 25 2010