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 A019654 Consider problem of placing N queens on an n X n board so that each queen attacks precisely k others. Here k=4 and sequence gives number of different solutions when N takes its maximal value. 11
 0, 0, 0, 1, 3, 40, 655, 16573 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,5 COMMENTS I would also like to get the sequences that give the maximal value of N. An answer to this comment: I would also like to get the sequences that give the maximal value of N. What is the maximum number of queens that can be placed on an n*n chessboard such that no two attack one another? The answer is n queens, which gives eight queens for the usual 8*8 board (Madachy 1979; Steinhaus 1999, p. 29). The number of different ways the n queens can be placed on an n*n chessboard so that no two queens may attack each other for the first few n are 1, 0, 0, 2, 10, 4, 40, 92, ... [From Claudio (lordofchaos000(AT)hotmail.com), May 31 2010] REFERENCES M. Gardner, The Colossal Book of Mathematics, 2001, p. 209. LINKS Eric Weisstein's World of Mathematics, Queens Problem [From Claudio (lordofchaos000(AT)hotmail.com), May 31 2010] CROSSREFS Cf. A051567-A051571, A051754-A051759. Sequence in context: A215196 A093376 A051571 * A156356 A143640 A260754 Adjacent sequences:  A019651 A019652 A019653 * A019655 A019656 A019657 KEYWORD nonn,nice,more AUTHOR N. J. A. Sloane, Oct 03 2002 EXTENSIONS I am not certain this description is correct, nor how rigorous the results are. STATUS approved

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