# A124535 (b-file synthesized from sequence entry) 0 1 1 1 2 6 3 36 4 216 5 961 6 5977 7 39363 8 271564 9 1949165 10 14487241 11 111115804 12 877086405 13 7109569724 14 59075905996 15 502464618671 16 4369068613929 17 38796820526316 18 351496911119002 19 3246426019892427 20 30543990287835441