1469991559domain: NAppears in sequencesa(n) = Sum_{i=1..n} (prime(i)^n - 1)/(prime(i) - 1).at n=7A124271Primes in A124271, or primes of the form Sum_{i=1..k} (prime(i)^k - 1)/(prime(i) - 1).at n=1A124272