# A089421 (b-file synthesized from sequence entry) 0 1 1 1 2 1 3 2 4 3 5 9 6 22 7 71 8 217 9 729 10 2438 11 8440 12 29414 13 104138 14 371516 15 1337649 16 4847637 17 17680265 18 64823110 19 238824212 20 883634026