# A006570 (b-file synthesized from sequence entry) 1 1 2 2 3 5 4 15 5 48 6 166 7 596 8 2221 9 8472 10 32995 11 130507 12 523100 13 2119454 14 8667529 15 35727261 16 148285069 17 619172847 18 2599212499 19 10963049307 20 46437309218 21 197454056586 22 842504023722 23 3606195947971 24 15480329150558 25 66628688247862 26 287475949517326 27 1243140817965661