# A107508 (b-file synthesized from sequence entry) 0 1 1 312 2 18642 3 447096 4 6004674 5 53600248 6 353024594 7 1839267768 8 7960151810 9 29653889720 10 97649896786 11 290078713080 12 789747027394 13 1995416563064 14 4726400795090 15 10581459177016 16 22543374588930 17 45962181162040 18 90105620342738 19 170538349148024 20 312685497919938