# A008551 (b-file synthesized from sequence entry) 0 2 1 0 2 0 3 128 4 0 5 384 6 3648 7 1920 8 20448 9 71680 10 125952 11 537600 12 1445440 13 3756288 14 11173440 15 29955072 16 79741908 17 214759680 18 564284736 19 1466972160 20 3794966880 21 9719376896 22 24675685440 23 62292331392 24 156254486400 25 389861188608