ThmDex – An index of mathematical definitions, results, and conjectures.
F13541
Formulation 0
Let $N \in \{ 1, 2, 3, \ldots \}$ be a D5094: Positive integer.
Then \begin{equation} - 1 = - 2^{N - 1} + \sum_{n = 0}^{N - 2} 2^n \end{equation}