Sheet tab labeling 1, 2,3... can I put sheet number as A1 inside formula?

Let me explain my worksheet.

My sheet tabs is labelled 1, 2, 3... to 28 representing each week.

I am wondering if I can put sheet number inside formula without changing sheet number manually and so that it will give me result I want?

like I tried A1: 1
A2 : 2
A3: 3

='A1'!$B$11

it would not allow me to label it as "A1 or A2 or A3" to make it '1'! or '2'! or '3'!. Any help or tips?

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