straight down order for automatically filling

[f_yec]

Hi everyone,
I want an order straight down for automatically filling in excel. Like this:
'=INDEX(Sheet2!$1:$1,(COLUMNS($A:A)-1)*2+1) &", "& INDEX(Sheet2!$2:$2,COLUMNS($A:A)*2)'
'=INDEX(Sheet2!$2:$2,(COLUMNS($A:A)-1)*2+1) &", "& INDEX(Sheet2!$2:$2,COLUMNS($A:A)*2)'
'=INDEX(Sheet2!$3:$3,(COLUMNS($A:A)-1)*2+1) &", "& INDEX(Sheet2!$3:$3,COLUMNS($A:A)*2)'
...
Can you write related code?
Thank you.