# A073966 (b-file synthesized from sequence entry) 1 1 2 2 3 6 4 20 5 125 6 625 7 3150 8 15500 9 78000 10 390625 11 1955625 12 9768750 13 48831250 14 244125000 15 1220703125 16 6103515625 17 30517656250 18 152587500000 19 762939062500 20 3814697265625 21 19073494140625 22 95367441406250 23 476837167968750 24 2384185742187500 25 11920928955078125