654022685443domain: NAppears in sequencesPrimes of the form k^6 + k^5 + k^4 + k^3 + k^2 + k + 1 where k is nonprime.at n=14A194194Primes of the form: 1 + sigma(n) + sigma(n)^2 + sigma(n)^3 + sigma(n)^4 + sigma(n)^5 + sigma(n)^6.at n=15A259253