# A007230 (b-file synthesized from sequence entry) 1 0 2 1 3 2 4 7 5 12 6 30 7 54 8 127 9 226 10 508 11 930 12 2046 13 3780 14 8182 15 15288 16 32767 17 61680 18 131042 19 248346 20 524284