Rudy's OBTF

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Solutions

\(n = 1\)-queens trivial,

(my-queens-render-solutions (my-queens 1 t))

\begin{flushleft} \chessboard[smallboard, maxfield=a1, setpieces={qa1}] \end{flushleft}

\(n = 2\) and \(n = 3\)-queens have no solutions

(list (length (my-queens 2 t))
      (length (my-queens 3 t)))

(0 0)

\(n = 4\)-queens has two solutions,

(my-queens-render-solutions (my-queens 4 t))

\begin{flushleft} \chessboard[smallboard, maxfield=d4, setpieces={qa3, qb1, qc4, qd2}] \chessboard[smallboard, maxfield=d4, setpieces={qa2, qb4, qc1, qd3}] \end{flushleft}

and the traditional \(n = 8\)-queens has

(length (my-queens 8 t))

solutions, one of them being

(my-queens-render-solutions (my-queens 8))

\begin{flushleft} \chessboard[smallboard, maxfield=h8, setpieces={qa6, qb3, qc5, qd7, qe1, qf4, qg2, qh8}] \end{flushleft}