# A020026 (b-file synthesized from sequence entry) 0 1 1 1 2 1 3 3 4 10 5 45 6 251 7 1666 8 12701 9 109544 10 1054364 11 11202617 12 130230419 13 1644159040 14 22401666926 15 327624378798 16 5119130918712 17 85105551523595 18 1499985345603354 19 27937227061862467 20 548268081089050918