# A285018 (b-file synthesized from sequence entry) 0 1 1 6 2 24 3 432 4 10368 5 6912 6 248832 7 1492992 8 23887872 9 1289945088 10 15479341056 11 30958682112 12 2229025112064 13 13374150672384 14 5944066965504 15 106993205379072 16 10271347716390912 17 20542695432781824 18 2218611106740436992 19 13311666640442621952 20 106493333123540975616