If n mod 10 is 1, 3, 7, or 9, then a(n) = least prime of the form 1 followed by n^r; else a(n) = least prime of the form n^r followed by a 1. In both cases r must be > 1 and a(n) = 0 if no such prime exists.

A089776

If n mod 10 is 1, 3, 7, or 9, then a(n) = least prime of the form 1 followed by n^r; else a(n) = least prime of the form n^r followed by a 1. In both cases r must be > 1 and a(n) = 0 if no such prime exists.