# A205825 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 3 4 12 5 20 6 120 7 210 8 1680 9 3024 10 30240 11 55440 12 665280 13 1235520 14 17297280 15 32432400 16 518918400 17 980179200 18 17643225600 19 33522128640 20 670442572800 21 1279935820800 22 28158588057600 23 53970627110400 24 1295295050649600 25 2490952020480000 26 64764752532480000