68719083519domain: NAppears in sequencesa(n)=16^n - 3*2^(2*n - 1) - 1.at n=8A152101Numbers of the form (2^p - 1)(2^q + 1) where p and q are twin primes.at n=3A152102Binary palindromic numbers with only two 0 bits, both in the middle.at n=16A220236