# A084518 (b-file synthesized from sequence entry) 1 1 2 2 3 5 4 18 5 65 6 238 7 877 8 3234 9 11929 10 44006 11 162341 12 598890 13 2209361 14 8150542 15 30068125 16 110924178 17 409209865 18 1509614198 19 5569110677 20 20544980154 21 75792390209 22 279605352286 23 1031490797581 24 3805267877730 25 14037995932921