# A005304 (b-file synthesized from sequence entry) 1 2 2 2 3 4 4 10 5 18 6 32 7 58 8 98 9 164 10 274 11 442 12 704 13 1114 14 1730 15 2660 16 4058 17 6114 18 9136 19 13554 20 19930