# A179600 (b-file synthesized from sequence entry) 0 1 1 3 2 16 3 66 4 304 5 1332 6 5968 7 26472 8 117952 9 524496 10 2334400 11 10385568 12 46213120 13 205619520 14 914912512 15 4070872704 16 18113348608 17 80595074304 18 358607125504 19 1595618388480 20 7099688329216 21 31589989045248 22 140559334936576