The 19th sequential twin prime is 109. Note, chapter 109 is called “The Unfaithful”. The 109thquad-prime is 748 which is the index of Lonely Prime 9127.
748 = 2 × 2 × 11× 17
The indices of these prime factors are 1 1 5 7. The number 1157 is semi-prime and its index is 341 = 11 × 31 and 1131stprime is 9127.
