# A004040 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 23 4 103 5 512 6 2740 7 15485 8 91245 9 555662 10 3475090 11 22214707 12 144640291 13 956560748 14 6411521056 15 43478151737 16 297864793993 17 2059159989914 18 14350039389022 19 100726680316559 20 711630547589023 21 5057282786190872 22 36132861123763276 23 259423620328055093 24 1870954187618001253