# A026580 (b-file synthesized from sequence entry) 0 1 1 2 2 5 3 12 4 30 5 75 6 189 7 478 8 1211 9 3076 10 7818 11 19901 12 50680 13 129179 14 329383 15 840336 16 2144540 17 5474889 18 13980493 19 35709394 20 91228015 21 233108456 22 595740568 23 1522725379 24 3892624055 25 9952119054 26 25446913766 27 65072487645