789062501domain: NPropertiesPrimalityPrimeyesAppears in sequencesOdd integers k such that 3^((k-1)/2) + 1 == 0 (mod k*(k-1)/2).at n=7A337828Odd integers k such that 7^((k-1)/2) + 1 == 0 (mod k*(k-1)/2).at n=9A337831Prime numbersat n=40612298