# A173190 (b-file synthesized from sequence entry) 1 1 2 8 3 6561 4 6912 5 7776 6 18432 7 52488 8 393216 9 708588 10 258280326 11 327680000 12 1000000000 13 2097152000 14 1007769600000 15 1612431360000 16 1813985280000 17 2149908480000 18 3936600000000 19 6122200320000 20 6561000000000 21 7652750400000