A twin prime is a pair of primes (x, y), such that y = x + 2.
Construct a list of all twin primes less than 1000. The result
should be stored in a list of numeric vectors called twin_primes,
whose elements are the twin primes pairs. Print the length of the
list twin_primes and print the 10th and the 15th elements of the
list, i.e. twin_primes[[10]] and twin_primes[[15]].
Please use R-code.