# A226933 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 3 4 6 5 60 6 360 7 70 8 336 9 756 10 75600 11 207900 12 9979200 13 25945920 14 1816214400 15 3405402000 16 504504000 17 308756448000 18 505237824000 19 52797352608000 20 1055947052160000 21 221748880953600 22 12196188452448000 23 280512334406304000 24 2692918410300518400 25 106557391987200000 26 972442759275187200000