542785domain: NAppears in sequencesNumber of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having directed index change -2,-2 -1,0 0,1 or 1,0.at n=23A264535Number of double cosets of the Sylow 2-subgroup of the symmetric group S_n.at n=14A360808