# A009247 (b-file synthesized from sequence entry) 0 1 1 1 2 1 3 6 4 21 5 92 6 597 7 3472 8 26537 9 209488 10 1834249 11 17750304 12 180938109 13 2024471360 14 23781199197 15 300235771648 16 3989919982673 17 56114783183104 18 830092069266577 19 12879188611161600 20 209479116176732901 21 3554985326516636672