Sequence Analysis: Letters Between Symbols

The question requires identifying letters within the sequence $RK59#B2%*E?A8LSI4SV7!C6N@H13D$ that are immediately surrounded by symbols.

Finding the Pattern

We need to find instances of the pattern: Symbol + Letter + Symbol.

Let's examine the sequence:

• Symbols present: $#$, $%$, $*$, $?$, $!$, $@$.
• Letters present: $R$, $K$, $B$, $E$, $A$, $L$, $S$, $I$, $V$, $C$, $N$, $H$, $D$.
• Numbers present: $5$, $9$, $2$, $8$, $4$, $7$, $6$, $1$, $3$.

Scanning for Matches

We scan the sequence for the target pattern:

• Around 'B': Preceded by $#$ (Symbol), followed by $2$ (Number). No match.
• Around 'E': Preceded by $*$ (Symbol), followed by $?$ (Symbol). This is a match. The pattern found is $*E?$.
• Around 'A': Preceded by $?$ (Symbol), followed by $8$ (Number). No match.
• Around 'C': Preceded by $!$ (Symbol), followed by $6$ (Number). No match.
• Around 'H': Preceded by $@$ (Symbol), followed by $1$ (Number). No match.

No other letters in the sequence are immediately preceded and followed by symbols.

Result Calculation

Only one letter ('E') satisfies the condition.

Therefore, the count is 1.