73712domain: NAppears in sequencesNumber of ways of placing n nonattacking queens on an n X n board.at n=13A000170Erroneous duplicate of A000170, see comments.at n=12A140393Prime power Giuga numbers: composite numbers n > 1 such that -1/n + sum 1/p^k = 1, where the sum is over the prime powers p^k dividing n.at n=13A286497