# A074502 (b-file synthesized from sequence entry) 0 3 1 9 2 41 3 225 4 1313 5 7809 6 46721 7 280065 8 1679873 9 10078209 10 60467201 11 362799105 12 2176786433 13 13060702209 14 78364180481 15 470185017345 16 2821109972993 17 16926659575809 18 101559956930561 19 609359740534785 20 3656158441111553