Euler numbers
From specialfunctionswiki
The Euler numbers $E_k$ are the coefficients in the following Taylor series for $|z| < \dfrac{\pi}{2}$: $$\mathrm{sech}(z) = \displaystyle\sum_{k=0}^{\infty} E_k \dfrac{z^n}{n!},$$ where $\mathrm{sech}$ denotes hyperbolic secant.
Properties
References
- 1953: Arthur Erdélyi, Wilhelm Magnus, Fritz Oberhettinger and Francesco G. Tricomi: Higher Transcendental Functions Volume I ... (previous) ... (next): $\S 1.14 (1)$
