# A077834 (b-file synthesized from sequence entry) 0 1 1 2 2 6 3 19 4 56 5 168 6 505 7 1514 8 4542 9 13627 10 40880 11 122640 12 367921 13 1103762 14 3311286 15 9933859 16 29801576 17 89404728 18 268214185 19 804642554 20 2413927662 21 7241782987 22 21725348960 23 65176046880 24 195528140641 25 586584421922 26 1759753265766 27 5279259797299 28 15837779391896