Signed Stirling Number of the First Kind of 1

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Theorem

$\map s {1, n} = \delta_{1 n}$

where:

$\map s {1, n}$ denotes a signed Stirling number of the first kind
$\delta_{1 n}$ is the Kronecker delta.


Proof

\(\ds \map s {1, n}\) \(=\) \(\ds \map s {0, n - 1} - 0 \times \map s {0, n}\) Definition of Signed Stirling Numbers of the First Kind
\(\ds \) \(=\) \(\ds \map s {0, n - 1}\)
\(\ds \) \(=\) \(\ds \delta_{0 \paren {n - 1} }\) Definition of Signed Stirling Numbers of the First Kind
\(\ds \) \(=\) \(\ds \delta_{1 n}\) $0 = n - 1 \iff 1 = n$

$\blacksquare$


Also see