# A037675 (b-file synthesized from sequence entry) 1 1 2 5 3 27 4 138 5 691 6 3455 7 17277 8 86388 9 431941 10 2159705 11 10798527 12 53992638 13 269963191 14 1349815955 15 6749079777 16 33745398888 17 168726994441 18 843634972205 19 4218174861027 20 21090874305138 21 105454371525691 22 527271857628455