169097domain: NPropertiesPrimalityPrimeyesAppears in sequencesLeast prime divisor of T(n) which does not divide any T(k) with k < n, or 1 if such a primitive prime divisor of T(n) does not exist, where T(n) is the n-th central trinomial coefficient given by A002426.at n=22A242170Boyd's Pisot-like sequence F(0,5,11).at n=25A274946Prime numbersat n=15421