# A068739 (b-file synthesized from sequence entry) 1 1 2 2 3 5 4 13 5 31 6 72 7 156 8 337 9 701 10 1452 11 2964 12 6001 13 12108 14 24324 15 48871 16 97988 17 196224 18 392768 19 785946 20 1572353 21 3145554 22 6291980