91491511domain: NPropertiesPrimalityPrimeyesAppears in sequencesConcatenate the primes as 2357111317192329313..., then insert commas from left to right so that between each pair of successive commas is a prime, always making the new prime as small as possible.at n=19A074721Erroneous version of A074721.at n=16A151796Prime numbersat n=5298515