# A173391 (b-file synthesized from sequence entry) 1 9 2 21 3 45 4 105 5 273 6 765 7 2229 8 6609 9 19737 10 59109 11 177213 12 531513 13 1594401 14 4783053 15 14348997 16 43046817 17 129140265 18 387420597 19 1162261581 20 3486784521 21 10460353329 22 31381059741 23 94143178965 24 282429536625 25 847288609593