# A051043 (b-file synthesized from sequence entry) 0 1 1 4 2 16 3 60 4 228 5 864 6 3264 7 12336 8 46632 9 176208 10 665892 11 2516412 12 9509364 13 35935476 14 135798588 15 513176076 16 1939267560 17 7328398344