Insert cell value as sheet name in VLOOKUP formula

[purplecherrymuffins]

Heeeelllo, I am not sure how this works, I've invested a lot of time into this, please help. Thanks so much.
So...
I have this formula, which works perfectly fine, but I want to make it more automatic right?
=IFNA(VLOOKUP(B5,IMPORTRANGE("mydocURL", "517!A:F"),6,FALSE), "0")

I have several columns and in each column all I do is change the sheet name, since my formula looks for the same from the same value every time
example
COLUMN 1 looks like this
=IFNA(VLOOKUP(B5,IMPORTRANGE("mydocURL", "517!A:F"),6,FALSE), "0")
=IFNA(VLOOKUP(B6,IMPORTRANGE("mydocURL", "517!A:F"),6,FALSE), "0")
=IFNA(VLOOKUP(B7,IMPORTRANGE("mydocURL", "517!A:F"),6,FALSE), "0")
and so on ..

then column two looks like this
=IFNA(VLOOKUP(B5,IMPORTRANGE("mydocURL", "551!A:F"),6,FALSE), "0")
=IFNA(VLOOKUP(B6,IMPORTRANGE("mydocURL", "551!A:F"),6,FALSE), "0")
=IFNA(VLOOKUP(B7,IMPORTRANGE("mydocURL", "551!A:F"),6,FALSE), "0")

Another person helps me fill out the sheet and she knows that the only change she must do is the three number (which is the NAME of the new sheet she insertsm it always is a 3 digit number, and it will never change. So I am trying to insert the value of a cell so I don't have to manually erase the numbers.
I hope I explained myself.
thanks

 

[Peter_SSs]

Welcome to the MrExcel board!

Is this a Google Sheets question?

 

[purplecherrymuffins]

Welcome to the MrExcel board!

Is this a Google Sheets question?

}

Hi! No, its Excel

 

[saeedkk]

Hello,
I believe Peter_SSs question is right, the IMPORTRANGE function isn't an MS excel function. it is a google sheet function.