# A111955 (b-file synthesized from sequence entry) 0 0 1 1 2 4 3 7 4 20 5 45 6 112 7 267 8 648 9 1561 10 3772 11 9103 12 21980 13 53061 14 128104 15 309267 16 746640 17 1802545 18 4351732 19 10506007 20 25363748 21 61233501 22 147830752 23 356895003 24 861620760 25 2080136521 26 5021893804 27 12123924127 28 29269742060 29 70663408245