# A000552 (b-file synthesized from sequence entry) 4 24 5 300 6 3360 7 38850 8 475776 9 6231960 10 87530400 11 1316954430 12 21173760960 13 362670636900 14 6596214691248 15 126980000240730 16 2579214238608000 17 55118036257959600 18 1235935135837111104 19 29009023670878484598