Bernoulli number
= Bernoulli number
{c}
{title2=$B_n$}
{wiki}
The Bernoulli numbers in the convention $B_1=-1/2$ are defined by $t/(e^t-1)=\sum_{n\geq0}B_nt^n/n!$. The first values are $1,-1/2,1/6,0,-1/30$. The function $t/(e^t-1)+t/2$ is even, so all odd-index values beyond $B_1$ vanish.