# A122939 (b-file synthesized from sequence entry) 0 1 1 2 2 3 3 6 4 17 5 70 6 390 7 2776 8 24042 9 244864 10 2862185 11 37715474 12 552685976 13 8910951840 14 156709821779 15 2984589501562 16 61188398397436 17 1343410717573876 18 31445844702847347 19 781689483100388326 20 20564696601659697997