124408576656domain: NAppears in sequencesa(n) = binomial(n, floor(n/2))^2 = A001405(n)^2.at n=21A018224a(0) = 1; for n > 0, binomial(2n-1, n-1)^2.at n=11A060150a(n) = binomial(n, floor((n-1)/2))^2.at n=21A378060a(n) = binomial(n - 1, ceiling(n/2)) * binomial(n - 1, ceiling(n/2) - 1).at n=22A378070