# A001898 (b-file synthesized from sequence entry) 0 1 1 2 2 12 3 8 4 240 5 96 6 4032 7 1152 8 34560 9 7680 10 101376 11 18432 12 50319360 13 7741440 14 6635520 15 884736 16 451215360 17 53084160 18 42361159680 19 4459069440 20 1471492915200 21 140142182400 22 1758147379200 23 152882380800 24 417368899584000 25 33389511966720 26 15410543984640