# A027295 (b-file synthesized from sequence entry) 1 1 2 4 3 15 4 52 5 195 6 676 7 2555 8 8976 9 34098 10 121448 11 463067 12 1669340 13 6384287 14 23251620 15 89157557 16 327523680 17 1258803182 18 4658150520 19 17940605163 20 66803546472 21 257777882894 22 965023761064 23 3730202020650 24 14029655954272 25 54315578806820 26 205120107930192