pub fn bernoulli_b2n<E: BernoulliNumbers>(n: usize) -> Option<E>Expand description
$B_{2n}$, or None when it is not tabulated: either $n = 0$, or $B_{2n}$
overflows E.
The argument is n as in $B_{2n}$, following the mathematics rather than the
slice index, so bernoulli_b2n::<f64>(1) is $B_2$, the first entry. Reach for
BernoulliNumbers::B2N directly when iterating, where entry i is $B_{2i+2}$.