# A012948 (b-file synthesized from sequence entry) 0 1 1 2 2 4 3 11 4 40 5 177 6 934 7 5665 8 39064 9 301209 10 2572314 11 24156365 12 247234332 13 2751134557 14 33003190406 15 426920246945 16 5905698391952 17 87530592395793 18 1378247307547506 19 23127717388170197 20 409930747848171812