The value of the smallest positive base ten integer that cannot be changed into a prime by changing a single digit was determined in Never prime!.

M denotes the smallest value of a base N positive integer that cannot be changed into a prime by changing a single digit.

For the values of N drawn at random between 51 and 100 inclusively, determine the probability that the first digit of M (reading left to right) is 3.

Note: N is a positive integer and, M cannot contain any leading zero, and the first digit of M (reading left to right) cannot be changed to a zero.