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 A018807 Number of ways to place n^2 nonattacking kings on 2n X 2n chessboard. 12
 1, 4, 79, 3600, 281571, 32572756, 5109144543, 1027533353168, 254977173389319, 75925129079783308, 26568150968269086211, 10749154284380665611224, 4963704194366362387891227, 2588716234142991968960920692, 1511548995678989691821551648635 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Rotations and reflections are considered distinct. Also, number of ways to tile a (2n+1) X (2n+1) board with n^2 2 X 2 tiles and 4n+1 1 X 1 tiles, rotations and reflections counted as distinct. - David W. Wilson, Aug 18 2011 Number of maximum independent vertex sets in the 2n X 2n king graph. - Eric W. Weisstein, Jun 20 2017 LINKS David W. Wilson, Table of n, a(n) for n = 0..26 Zealint Blog (Russian) Source for a(12) through a(20), March 14 2011. a(21) through a(26) from same source, July 9 2011. V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, pp. 160-162. Michael Larsen, The Problem of Kings, The Electronic Journal of Combinatorics 2, 1995 Eric Weisstein's World of Mathematics, King Graph Eric Weisstein's World of Mathematics, Maximum Independent Vertex Set FORMULA Asymptotic (M. Larsen, 1995): log(a(n)) = 2n*log(n) - 2n*log(2) + O(n^(4/5)*log(n)). CROSSREFS Cf. A174558, A174155, A174154, A173782, A173783, A061594, A061593. Sequence in context: A048957 A006425 A065930 * A216410 A125710 A204296 Adjacent sequences:  A018804 A018805 A018806 * A018808 A018809 A018810 KEYWORD nonn,nice AUTHOR EXTENSIONS a(0) added by Geoffrey H. Morley, Feb 06 2013 STATUS approved

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Last modified November 12 19:19 EST 2018. Contains 317116 sequences. (Running on oeis4.)