# A153926 (b-file synthesized from sequence entry) 0 1 1 2 2 2 3 3 4 5 5 6 6 12 7 35 8 83 9 231 10 918 11 2132 12 7575 13 42734 14 132320 15 609928 16 4694085 17 18109624 18 113969565 19 1148801096 20 6065910343 21 51213901318