# A102355 (b-file synthesized from sequence entry) 0 0 1 1 2 2 3 120 4 121 5 201 6 2120 7 12120 8 121201 9 212012 10 12012120 11 12120121 12 20121201 13 212012120 14 1212012120 15 12120121201 16 21201212012 17 1201212012120 18 1212012120121 19 2012120121201 20 21201212012120 21 121201212012120