16692551domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes p such that phi(p+1) = phi(p-1).at n=26A067890Lesser of twin primes p for which phi(p-1) = phi(p+1), where phi(n) is the Euler totient function (A000010).at n=5A303549Prime numbersat n=1072766