# A181367 (b-file synthesized from sequence entry) 1 2 2 6 3 22 4 78 5 272 6 940 7 3232 8 11080 9 37920 10 129648 11 443008 12 1513248 13 5168000 14 17647552 15 60258304 16 205746304 17 702484992 18 2398480128 19 8189016064 20 27959235072 21 95459170304 22 325918735360 23 1112757649408 24 3799195224064