Group similar columns in one column

[f.guern]

Dear everyone,
I am a french phd in sociology and i have found your forum as I am working with excel.

In my excel sheet I have lots of column of the same year for various articles studies. My first two rows are :

1922 / 1922 / 1922 / 1923 / 1923 / 1923 / 1923 / etc.
bstj 1-1 / bstj 1-2 / bstj 1-3 / bstj 2-1/ bstj 2-2 / bstj 2-3 / bstj 2-4 / etc

I just want to put all the information of the year 1922 in the Column A. All the information of the year 1923 in the column B. This way, I will be able to search for duplicates.

Here a formula I found to turn all the column into a single one :
=OFFSET($A$1;MOD(ROW($A1)-1;COUNTA($A$1:$A$10));INT((ROW($A1)-1)/COUNTA($A$1:$A$1

But I don't know how to adapt this formula to use a index / match for the first line.

Do you have an idea ?
Thanks a lot by advance !
f.