Genocchi numbers
From specialfunctionswiki
The Genocchi numbers $G_n$ are given by the generating function $$\dfrac{2t}{e^t+1} = \displaystyle\sum_{k=0}^{\infty} G_n \dfrac{t^n}{n!}.$$
Properties
Proposition: The following values hold for the Genocchi numbers: $$G_1=1, G_3=G_5=G_7=G_9=G_11=\ldots=0.$$
Proof: █
Proposition: The following formula holds: $$G_{2n}=2(1-2^{2n})B_{2n}= 2nE_{2n-1}(0),$$ where $G_{2n}$ denotes Genocchi numbers, $B_{2n}$ denotes Bernoulli numbers, and $E_{2n-1}$ denotes an Euler polynomial.
Proof: █
