# A060955 (b-file synthesized from sequence entry) 1 1 2 1 3 1 4 3 5 5 6 10 7 35 8 70 9 216 10 567 11 2310 12 5775 13 21450 14 69498 15 243243 16 1153152 17 3620864 18 16336320 19 64664600 20 249420600 21 997682400 22 5462865408 23 21422145536