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 A143870 Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard. 6
 1, 2, 11, 91, 1462, 38483, 1755113, 140404442, 19400886875, 4764856837927, 2050537030592506, 1572046460892726633, 2133798146501117397613, 5167591018292995062973870, 22288638410038000574365307819, 171813750317653145879779979300275, 2366759768251260378737273078723819964 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS R. H. Hardin, Table of n, a(n) for n = 0..26 EXAMPLE Configurations of 0,1,2,3 or 4 kings on an 2 X 2 chessboard and the number of mutual attacks: .. .. .. K. .K .. K. KK .K .K K. K. .K KK KK KK .. K. .K .. .. KK K. .. .K K. .K KK KK .K K. KK 0 0 0 0 0 1 1 1 1 1 1 3 3 3 3 6 From 16 configurations is 11 with no more than 1 mutual attack, a(2)=11. CROSSREFS Cf. A143875, A143881, A143886. Cf. A143871, A143872, A143873, A143874. Diagonal of A268781. Sequence in context: A266656 A094955 A352292 * A047854 A366402 A222080 Adjacent sequences: A143867 A143868 A143869 * A143871 A143872 A143873 KEYWORD nonn AUTHOR R. H. Hardin, Sep 04 2008 EXTENSIONS Example added by Vaclav Kotesovec, Oct 20 2014 Additional terms from R. H. Hardin, Feb 13 2016 STATUS approved

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Last modified April 14 12:23 EDT 2024. Contains 371661 sequences. (Running on oeis4.)