99228108222domain: NAppears in sequencesNumber of general plane trees whose n-th subtree from the left is equal to the n-th subtree from the right, for all its subtrees (i.e., are palindromic in the shallow sense).at n=23A073192Convolution of A000108 (Catalan numbers) with A126120 (Catalan numbers interpolated with 0's).at n=22A161006