The problem of determining how many nonattacking knights K(n) can be placed on an n×n chessboard. For n = 8, the solution is 32 (illustrated above). In general, the solutions are K(n) = {1/2 n^2 | n>2 even 1/2(n^2 + 1) | n>1 odd, auto right match giving the sequence 1, 4, 5, 8, 13, 18, 25, ... (OEIS A030978, Dudeney 1970, p. 96; Madachy 1979).