1476368domain: NAppears in sequencesa(n) = T(2*n,n), T given by A026736.at n=11A026737a(n) = T(n, floor(n/2)), T given by A026736.at n=22A026742Number of permutations avoiding the patterns {3241,3421,4321}; number of weak sorting class based on 3241.at n=12A111279