# A135489 (b-file synthesized from sequence entry) 0 1 1 4 2 12 3 42 4 148 5 540 6 1990 7 7434 8 27972 9 106008 10 403764 11 1544796 12 5931486 13 22846252 14 88228998 15 341518606 16 1324627044 17 5146959168 18 20030812360 19 78066774400 20 304643526276 21 1190209498344 22 4654949367204 23 18223301727108