140473domain: NPropertiesPrimalityPrimeyesAppears in sequencesPrimes in A103378.at n=20A103388Quotient of the decimal representation of concatenated twin primes in reverse divided by 3.at n=21A129910Primes in A129910.at n=6A129911Smallest prime factor of A001008(n), numerator of n-th harmonic number; a(1) = 1.at n=42A308970Prime numbersat n=13050