723167domain: NPropertiesPrimalityPrimeyesAppears in sequencesPatterns in a dual ring.at n=22A007574Let P(x) = (x^2+1)^2+1; then a(n) is the lesser term of a twin prime pair such that P(a(n)) is also the lesser term of another twin prime pair.at n=21A093189Prime numbersat n=58275