# A001771 (b-file synthesized from sequence entry) 1 1 2 5 3 9 4 17 5 21 6 29 7 45 8 177 9 18381 10 22529 11 24557 12 26109 13 34857 14 41957 15 67421 16 70209 17 169085 18 173489 19 177977 20 363929 21 372897