the numbers are all prime and odd numbers
11, 13,17,19,23,29,31,37,
so the numbers are 1,3,7,9
because
2 is even and if it ends in 2 then divisible by 2
this crosses out all the even numbers :2,4,6,8
if it ends with 5 then it is divisible by 5 cross 5 out
so the numbers are 1,3,7,9
if the number ends with these number that doesn't mean that it is always prime exg 21 is not prime, 49 is not prime
so the numbers 1,3,7,9
