# A007851 (b-file synthesized from sequence entry) 1 1 2 4 3 14 4 48 5 167 6 593 7 2144 8 7864 9 29171 10 109173 11 411501 12 1560089 13 5943199 14 22732739 15 87253604 16 335897864 17 1296447899 18 5015206349 19 19439895089 20 75487384829 21 293595204239 22 1143532045499 23 4459774977449 24 17413705988873