# A067971 (b-file synthesized from sequence entry) 0 1 1 5 2 25 3 105 4 678 5 2685 6 6631 7 17248 8 48056 9 109016 10 255085 11 576468 12 1026598 13 2161819 14 4793623 15 10107506 16 21624889 17 46584891 18 100042239 19 215671305 20 464309988 21 1000305876 22 2156229901 23 4642492109 24 10000266599