# A296665 (b-file synthesized from sequence entry) 0 1 1 4 2 20 3 96 4 444 5 2000 6 8840 7 38528 8 166124 9 710256 10 3016056 11 12736064 12 53530840 13 224107936 14 935062544 15 3890018816 16 16141765964 17 66829954736 18 276135664664 19 1138932645056 20 4690042582664 21 19285299964256 22 79196366286704 23 324835930747136 24 1330905207444344