# A309811 (b-file synthesized from sequence entry) 1 1 2 2 3 6 4 12 5 60 6 120 7 360 8 2520 9 5040 10 55440 11 720720 12 2162160 13 4324320 14 73513440 15 367567200 16 6983776800 17 160626866400 18 321253732800 19 9316358251200 20 288807105787200 21 2021649740510400 22 74801040398884800 23 224403121196654400 24 9200527969062830400 25 395622702669701707200