1, 2, 3, 4, ..., 23, 24, 25, 26, ?
The data above are very likely natural numbers and there is no reason for not replacing the question mark with 27. But would a true atheist replace "?" with the number of books in The New Testament? The question mark is a symbol that ends questions, and questions are answered the best with the help of scientific atheism, coz the rational answers can't be found in the 27 books of The New Testament where Jesus is the hero. So if you replace the missing number with 27, then you are a false atheist, not a true atheist. Of course, by chosing other number than 27, you flunk the admission test to the kindergarten, BUT the atheists are here to suffer for all of us. God bless them profusely and vehemently.