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 A294240 The number of possible ways in which 2*n^2 black pawns and 2*n^2 white pawns can be arranged on a 2n X 2n chessboard such that no pawn attacks another. 0
 1, 3, 30, 410, 6148, 96120, 1526700, 24425026, 392143828, 6306613690, 101505099104, 1634209596410, 26311180850268, 423567557239604, 6817440328754244, 109703307312544664, 1764863031686159684, 28385338557467333804, 456426743658724223028, 7337464027218416593362 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS White pawns attack diagonally up and black pawns attack diagonally down. En passant capturing is not possible. LINKS Table of n, a(n) for n=0..19. Code Golf Stack Exchange user feersum, Too many pawns on a chess board. EXAMPLE For n = 1 the a(1) = 3 boards are as follows: +---+---+ +---+---+ +---+---+ | W | W | | B | W | | W | B | +---+---+ +---+---+ +---+---+ | B | B | | W | B | | B | W | +---+---+ +---+---+ +---+---+ . An example of one of the a(2) = 30 boards is: +---+---+---+---+ | W | W | W | W | +---+---+---+---+ | B | W | W | W | +---+---+---+---+ | B | B | W | B | +---+---+---+---+ | B | B | B | B | +---+---+---+---+ CROSSREFS Cf. A035290. Sequence in context: A234506 A212425 A336538 * A007004 A354291 A354287 Adjacent sequences: A294237 A294238 A294239 * A294241 A294242 A294243 KEYWORD nonn AUTHOR Peter Kagey, Oct 25 2017 STATUS approved

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Last modified June 5 16:06 EDT 2023. Contains 363137 sequences. (Running on oeis4.)