There is a composite number that's the sum of three 3-digit primes of the following sort: The first and the last digit are each 1-digit primes, and the first two digits taken together, as well as the last two digits taken together, are each 2-digit primes.
What are the three 3-digit primes that sum to the composite number in question?
The three required primes are:313, 317, and 373.