25613280domain: NAppears in sequencesDenominator of Sum_{k=0..2*n} (-1)^k/binomial(2*n, k)^2.at n=6A100521Number of ways to place 5 nonattacking bishops on an n X n toroidal board.at n=10A177758Number of non-attacking placements of 5 rooks on an n X n board.at n=10A179060