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 A181499 Triangle read by rows: number of solutions of n queens problem for given n and given number of conflicts 4
 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, 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, 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 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,13 LINKS Matthias Engelhardt, Table of n, a(n) for n = 0..152 (corrected by Michel Marcus, Jan 19 2019) M. Engelhardt, Conflicts in the n-queens problem M. 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 Row sum = A000170 (number of n queens placements) Column 0 has same values as A007705 (torus n queens solutions) Column 1 is always zero. EXAMPLE 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 Cf. A000170, A007705, A181500, A181501, A181502. Sequence in context: A350487 A258759 A350793 * A010893 A181501 A213704 Adjacent sequences: A181496 A181497 A181498 * A181500 A181501 A181502 KEYWORD nonn,tabl AUTHOR Matthias Engelhardt, Oct 25 2010 STATUS approved

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Last modified September 13 03:07 EDT 2024. Contains 375857 sequences. (Running on oeis4.)