func bernoulli_number(n) is cached {

    n.is_one && return 1/2
    n.is_odd && return   0

    1 - sum(^n, {|k|
        binomial(n,k) * __FUNC__(k) / (n - k + 1)
    })
}

for n in (0..60) {
    var Bn = bernoulli_number(n) || next
    printf("B(%2d) = %44s / %s\n", n, Bn.nude)
}