Calculate the Gödel number of the band function

Question

I am looking at the following:

Compute the Gödel number of the tape function that describes the band on which the word COMPREHENSIBILITY stands, where the symbol $H$ is written on Tape at position $0$. The rest of the tape is empty. The indexing of the characters should be in alphabetical order, i.e. $C \rightarrow 1$, $E \rightarrow 2$, etc.

$$$$

Could you explain to me what "the symbol $H$ is written on Tape at position $0$" means?

How can we use this information?

The word COMPREHENSIBILITY has $17$ letters. So do we consider the first $17$ prime numbers and take as exponents the indices of each letter to calculate the Gödel number?

Answer 1

It probably means that you only encode the part of the word starting with the $H$ ... the letters before the $H$ are in the 'negative' part of the tape and don't get encoded (which is weird ... but hey)

Also, the $B$ comes before the $C$, so the indexing should be::

$B \to 1$

$C \to 2$

$E \to 3$

$H \to 4$

$I \to 5$

$L \to 6$

$M \to 7$

$N \to 8$

$O \to 9$

$P \to 10$

$R \to 11$

$S \to 12$

$T \to 13$

$Y \to 14$

So, the coding is:

$$2^4 \cdot 3^3 \cdot 5^8 \cdot 7^{11} \cdot 11^5 \cdot 13^1 \cdot 17^5 \cdot 19^6 \cdot 23^5 \cdot 29^{13} \cdot 31^{14}$$