substituting `=' for `:', as in \*(lqname=n\*(rq. This will reduce
the selection from being a range of up to `n' messages, to being a
selection of just the `n'th message. So while \*(lqseq:5\*(rq
-selects the first 5 messages of seqence `seq', \*(lqseq=5\*(rq
+selects the first 5 messages of sequence `seq', \*(lqseq=5\*(rq
selects just the 5th message of the sequence. It is
an error if the requested message does not exist (i.e., there aren't
at least `n' messages in the sequence).