
Define an emirpimes ("semiprime" spelled backwards) as a semiprime whose (base 10) reversal is a different semiprime. The
first such number is 15, because 15 reversed is 51 and both 15 and 51 are semiprimes
(i.e., and
). A list of the first emirpimeses (or "semirpimes")
are 15, 26, 39, 49, 51, 58, 62, 85, 93, 94, 115, 122, 123, ... (OEIS A097393).
A binary plot of the semirpimes is illustrated above.
The numbers of semirpimes less than for
, 2, ... are 0, 10, 90, 898, 7200, 60732, ... (OEIS A097394).