# A007357 (b-file synthesized from sequence entry) 1 6 2 60 3 90 4 36720 5 12646368 6 22276800 7 126463680 8 4201148160 9 28770487200 10 287704872000 11 1446875426304 12 2548696550400 13 14468754263040 14 590325173932032 15 3291641594841600 16 8854877608980480 17 32916415948416000