# A028032 (b-file synthesized from sequence entry) 0 1 1 20 2 255 3 2650 4 24521 5 210840 6 1725235 7 13631750 8 104995341 9 793395460 10 5908353815 11 43502236050 12 317443722961 13 2299938136880 14 16567618807995 15 118785894675550 16 848393691575381 17 6040178746163100 18 42890062369599775 19 303884399490790250 20 2149118961443240601