Definition:Harmonic Sequence

Definition
A harmonic progression is a sequence $\left \langle{a_k}\right \rangle$ in $\R$ defined as:
 * $h_k = \dfrac 1 {a + k d}$

where:
 * $k \in \left\{ {0, 1, 2, \ldots}\right\}$
 * $-\dfrac a d \notin \left\{ {0, 1, 2, \ldots}\right\}$

Thus its general form is:
 * $\dfrac 1 a, \dfrac 1 {a + d}, \dfrac 1 {a + 2 d}, \dfrac 1 {a + 3 d}, \ldots$