# A026666 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 10 4 20 5 42 6 84 7 196 8 392 9 842 10 1684 11 3878 12 7756 13 16786 14 33572 15 76846 16 153692 17 333998 18 667996 19 1523448 20 3046896 21 6639150 22 13278300 23 30206468 24 60412936 25 131892226 26 263784452 27 598952096 28 1197904192 29 2619074230