#/***********************************************************
#    bernoull.rb -- Bernoulli (ベルヌーイ) 数
#***********************************************************/

def gcd( x,  y )  # 最大公約数 
    while (y != 0);  t = x % y;  x = y;  y = t;  end
    return x
end

N = 40
DBL_EPSILON = 2.2204460492503131e-16

t = []
(N+1).times { t.push(0) }

q = 1
t[1] = 1
for n in 2..N
    for i in 1...n; t[i - 1] = i * t[i]; end
    t[n - 1] = 0
    n.downto(2) {|i| t[i] += t[i - 2] }
    if (n % 2 == 0) 
        q *= 4
        b1 = n * t[0];  b2 = q * (q - 1)
        if (b1 < 1 / DBL_EPSILON && b2 < 1 / DBL_EPSILON) 
            d = gcd(b1, b2);  b1 /= d;  b2 /= d
            printf("|B(%2d)| = %.0f/%.0f\n", n, b1, b2)
        else
            printf("|B(%2d)| = %g\n", n, b1 / b2)
        end
    end
end

exit 0