512657domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes p such that sigma(p-1)+sigma(p+1) is prime.at n=18A067464a(n) is the largest prime of the form x^2 + 1 <= 2^n.at n=18A083849Primes of the form 81*k^2 - 72*k + 17.at n=9A154276Prime numbersat n=42487