Definition:Keith Number

Definition
Let $K \in \Z_{>9}$ be an $n$-digit integer, where $n > 1$.

Let $A = \left({a_1, a_2, \ldots, a_n}\right)$ be the digits of $K$ in order.

Let $F_A$ be the Fibonacci-like sequence on $A$.

Then $K$ is a Keith number $K$ occurs somewhere in $F_A$.

Also known as
A Keith number is referred to by some sources as a repfigit (repetitive fibonacci-like digit) number.