# A049070 (b-file synthesized from sequence entry) 0 0 1 2 2 27 3 224 4 1500 5 8910 6 49049 7 256256 8 1288872 9 6298500 10 30093910 11 141210432 12 652860520 13 2981331990 14 13472983125 15 60343756800 16 268187306640 17 1183875281820 18 5194996380090 19 22676052360000 20 98513956031400 21 426171522716940 22 1836562780483002