384049domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = Sum_{k = 1..n} T(k,k-1), where T is the array defined in A024996.at n=13A026079Primes p such that p*(p-2) divides 3^(p-1)-1.at n=22A081764Prime numbersat n=32607