# A371138 (b-file synthesized from sequence entry) 0 1 1 0 2 0 3 6 4 12 5 40 6 2340 7 18648 8 154560 9 5767200 10 95911200 11 1438778880 12 48014778240 13 1228487644800 14 27997623029376 15 972327510000000 16 32550437645107200 17 1006902423902269440 18 38894136241736494080 19 1569697954634035537920 20 61093442927846310912000