Integers with Prime Values of Divisor Sum/Mistake

Source Work

 * The Dictionary
 * $16$
 * $16$

Mistake

 * $\map \sigma {16} = 31$ is prime. The sequence of $n$ for which $\map \sigma n$ is prime runs: $2, 4, 9, 16, 25, 289 \ldots$

This is incorrect.

The correct sequence is:
 * $2, 4, 9, 16, 25, 64, 289 \ldots$