# A155580 (b-file synthesized from sequence entry) 0 1 1 1 2 2 3 5 4 10 5 30 6 180 7 585 8 1430 9 3575 10 9100 11 31850 12 83300 13 220150 14 792540 15 11888100 16 32167800 17 87567900 18 1576222200 19 4334611050 20 11971782900 21 33194488950 22 92367273600 23 257858638800 24 722004188640 25 18050104716000