Post date: Dec 18, 2019 4:16:29 PM
89 and 97 are the first pair of consecutive primes differing by 8.
89 is the 11th Fibonacci number.
Double 89 and add 1: repeat, to get a sequence of 6 primes: 89, 179, 359, 719, 1439, 2879. This is the smallest "Cunningham chain" of 6 primes.
Add the squares of the digits of any number and repeat this process. Eventually you get stuck at 1 (in which case the number that you started with is called "happy") or in the cycle 89, 145, 42, 20, 4, 16, 37, 58, 89.