What do tekler and çiftler mean in the seating chart of a theatre/concert hall?

i am not sure if i understood your question good but tek is single/only and çift is pair.

tekler (those that have no pair)

çiftler (pairs)

the odd numbers and the even numbers

Those terms  refer to ´´ odd numbers ´´ [Tek sayılar ] and "even numbers" [ çift sayılar ] 

I have just looked at " Ankara Opera Salon seating plan" and in that plan it is pointing odd numbers as " tekler" and even numbers as "çiftler " 

as tunci hocam explained above, çiftler indicates "seats with even numbers" and tekler "seats with odd numbers"  

Oh I see it now, thanks.

This explanation never came to my mind. I thought those who come alone are placed on the other side...