# A027120 (b-file synthesized from sequence entry) 2 2 3 7 4 20 5 56 6 155 7 429 8 1188 9 3298 10 9181 11 25634 12 71781 13 201569 14 567538 15 1601971 16 4532460 17 12851882 18 36516613 19 103955432 20 296471643 21 846932919 22 2423256440 23 6943726380 24 19924638557 25 57247669927 26 164688166948 27 474323305547