# A124714 (b-file synthesized from sequence entry) 0 1 1 21 2 61 3 141 4 377 5 1001 6 2737 7 7553 8 21073 9 59217 10 167441 11 475793 12 1357637 13 3887541 14 11165509 15 32152901 16 92802433 17 268398401 18 777651553 19 2256800033 20 6558953917 21 19087539437 22 55614451789 23 162219429293 24 473648632141