Find the largest pair of two-digit consecutive prime numbers a and b (with a<b ) such that the sum of the digits of a plus the sum of the digits of b is also a prime number. Write the concatenation of a and b.
Find the largest pair of two-digit consecutive prime numbers a and b (with a<b ) such that the sum of the digits of a plus the sum of the digits of b is also a prime number. Write the concatenation of a and b.