# A049143 (b-file synthesized from sequence entry) 1 1 2 1 3 2 4 4 5 10 6 26 7 74 8 219 9 678 10 2160 11 7062 12 23538 13 79734 14 273600 15 948972 16 3320845 17 11708586 18 41546434 19 148236556 20 531446460 21 1913357426 22 6914471176 23 25071324984 24 91181690872 25 332528253078 26 1215726924628 27 4454924130364