# A047047 (b-file synthesized from sequence entry) 0 1 1 3 2 9 3 28 4 90 5 311 6 1099 7 3928 8 14151 9 52025 10 193192 11 721507 12 2704857 13 10219356 14 38814183 15 147936398 16 565229232 17 2167575626 18 8337587694 19 32144302453 20 124143606307 21 480449680735 22 1862906012700 23 7234641087486 24 28131953989641