
COMMENTS

All prime numbers of the form 16*(10^k  1)/3 + 1 are terms of A002476.
For any k = a(n), the mindex of 16*(10^k  1)/3 + 1 in sequence 6m+1 contains exactly a(n) digits, and each digit is 8. E.g., while k = a(1) = 6, 16*(10^6  1)/3 + 1 = 6*888888 + 1 = 5333329.
In any number of form 16*(10^k  1)/3 + 1, its first digit is 5, its two last digits are 29, and each other digit that is between (5...29) is 3.
For k=1, k=2, k=3, the numbers of form 16*(10^k  1)/3 + 1 are squares of the primes 7, 23, and 73, respectively (see A001248).
