# A001902 (b-file synthesized from sequence entry) 0 1 1 1 2 3 3 9 4 45 5 75 6 175 7 1225 8 11025 9 19845 10 43659 11 160083 12 693693 13 1288287 14 2760615 15 41409225 16 703956825 17 1329696225 18 2807136475 19 10667118605 20 44801898141 21 85530896451 22 178837328943 23 1371086188563 24 11425718238025