# A005368 (b-file synthesized from sequence entry) 0 1 1 0 2 1 3 3 4 6 5 15 6 42 7 109 8 320 9 979 10 3137 11 10603 12 37728 13 140423 14 546859 15 2220294 16 9374309 17 41059926 18 186149869 19 871717073 20 4208841555 21 20917405824 22 106849492793