# A227461 (b-file synthesized from sequence entry) 1 1 2 2 3 12 4 128 5 1920 6 37104 7 877184 8 24520320 9 791112960 10 28932902400 11 1182789053952 12 53447706998784 13 2645389044480000 14 142326283714836480 15 8270318699325112320 16 516187815998727389184 17 34440412737701955502080 18 2446191865021002009477120 19 184278436717136012676956160