255374domain: NAppears in sequencesa(n) = 2 * A000538(n).at n=14A259108a(n) is the number of solutions to x^y == y^x (mod p) where 0 < x,y <= p^2 - p and p is the n-th prime.at n=16A355069Number of subsets of {1..n} with a subset summing to n.at n=18A365376