# A338437 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 9 4 32 5 300 6 864 7 17612 8 74752 9 1152792 10 6470400 11 220057992 12 719622144 13 40754156352 14 192835098624 15 4787867880000 16 55181218873344 17 3071730630989952 18 11004144881762304 19 1179255538492239744 20 5720352215040000000 21 253837962769406045184 22 3262870639485701849088