12880883408domain: NAppears in sequencesNumber of binary rooted trees of height n requiring 3 registers.at n=14A006223Number of walks in the first quadrant starting and ending at (0,0) consisting of 3n steps taken from {E=(1, 0), D=(-1, 1), S=(0, -1)}, no S step occurring before the final E step.at n=14A274969