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 A309260 Number of ways of placing 2n-1 nonattacking rooks on a hexagonal board with edge-length n in Glinski's hexagonal chess, inequivalent up to rotations and reflections of the board. 4
 1, 1, 1, 5, 29, 224, 3012, 55199, 1259765 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS A rook in Glinski's hexagonal chess can move to any cell along the perpendicular bisector of any of the 6 edges of the hexagonal cell it's on (analogous to a rook in orthodox chess which can move to any cell along the perpendicular bisector of any of the 4 edges of the square cell it's on). LINKS Chess variants, Glinski's Hexagonal Chess Vaclav Kotesovec, All inequivalent solutions for n = 2,3,4 and 5 Wikipedia, Hexagonal chess - GliĆski's hexagonal chess EXAMPLE a(1) = 1 .   o . a(2) = 1 .    o .   . . o    o . . a(3) = 1 .     o . .    . . o .   . . . . o    o . . .     . o . . a(4) = 5 .      o . . .        o . . .        o . . .        . o . .        . o . .     . . o . .      . . o . .      . . . o .      o . . . .      . . . . o    . . . . o .    . . . . . o    . . . . . o    . . . . . o    o . . . . .   . . . . . . o  . o . . . . .  . . o . . . .  . . . o . . .  . . . o . . .    o . . . . .    . . . . . o    o . . . . .    . . . . . o    . . . . . o     . o . . .      . . o . .      . . . . o      o . . . .      o . . . .      . . o .        o . . .        . o . .        . o . .        . . o . . CROSSREFS Cf. A000903, A002047, A003215, A309746, A309669. Sequence in context: A094856 A057623 A182018 * A087662 A113012 A000354 Adjacent sequences:  A309257 A309258 A309259 * A309261 A309262 A309263 KEYWORD nonn,more AUTHOR Sangeet Paul, Jul 19 2019 EXTENSIONS a(8) from Vaclav Kotesovec, Aug 16 2019 a(9) from Vaclav Kotesovec, Aug 23 2019 STATUS approved

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Last modified May 16 03:46 EDT 2021. Contains 343937 sequences. (Running on oeis4.)