the wrong number / a wrong number

[herbivorie]

This is a part of an email to a hotel.
Someone made a mistake when he booked a hotel online.

"I seem to have entered a wrong number of people when I made the reservation. I'm going to stay alone, but I wrongly entered the number of people as two. Could you please change it to one person?"

Should he say "a wrong number" or "the wrong number"?

 

[canadian45]

This is a part of an email to a hotel. You can omit the first "a".
Someone made a mistake when he booked a hotel online.

"I seem to have entered a wrong number of people when I made the reservation. I'm going to stay alone, but I wrongly entered the number of people as two. Could you please change it to one person?"

Should he say "a wrong number" or "the wrong number"?

You asked an interesting question. Theoretically, you can say 'a wrong number', because there were many possible wrong numbers. But the natural and correct answer is 'the wrong number'.

 

[AlexAD]

Disclaimer: Not a teacher. The correctness of the statements below should be verified.

This is part of the email to a hotel.

I would suggest you use the definite article with the email in your sentence as it is addressed to the hotel.

As for your original question, the indefinite article is not working here because you're referring to the number you entered.

I use this simple rule when I cannot decide which article to use.
As you may well know, the is a derivative of this/these/that/those whereas a/an is a derivative of one.
Thus replacing articles with their origins may help you to make a decision.

'This is part of this email to one hotel' vs 'This is part of one email to one hotel'
'I seem to have entered one wrong number' vs 'I seem to have entered this wrong number'

Addition: However, you say you picked a wrong number for the hash function, because there's more than one right number.