# A308700 (b-file synthesized from sequence entry) 0 0 1 0 2 2 3 18 4 112 5 600 6 2976 7 14112 8 65024 9 293760 10 1308160 11 5761536 12 25153536 13 109025280 14 469704704 15 2013143040 16 8589672448 17 36506664960 18 154617643008 19 652832538624 20 2748773826560 21 11544861081600 22 48378488553472 23 202310091276288 24 844424829468672 25 3518436999168000