# A052567 (b-file synthesized from sequence entry) 0 1 1 1 2 6 3 48 4 504 5 6600 6 103680 7 1900080 8 39795840 9 937681920 10 24548832000 11 706966444800 12 22210346188800 13 755916735974400 14 27706219904563200 15 1088037381150720000 16 45576301518139392000 17 2028445209752113152000 18 95589693062063456256000 19 4754884242802394308608000