# A074002 (b-file synthesized from sequence entry) 1 0 2 0 3 6 4 6 5 30 6 72 7 252 8 756 9 2106 10 6642 11 19602 12 59292 13 176904 14 530712 15 1596510 16 4780782 17 14351094 18 43040160 19 129146724 20 387440172 21 1162202418